243 or 270 for short barrels?


PDA






Grey Morel
May 16, 2010, 04:45 PM
I'm researching the performance of various calibers in short barrels for use in a dual application.

Since this gun will pull double duty as short to medium range varmint gun, as well as a brush gun, I'm focusing on high muzzle velocity and flat trajectories rather than muzzle energy.

My research indicates that the 243 and 270 are the two best contenders for highest velocity in a short barrel among the common hunting cartridges.

The dilemma reveals itself when you take into account different bullet weights: the 270 is the clear winner when using bullets from its lighter end (100-100gr), but the 243 is the best overall contender, maintaining high velocities across its entire range of projectile weights.

The 30 calibers are out; even though they may have more energy, they also have as much as 50% more drop at longer ranges when fired from a short barrel.

So what do you think? Should I go 270 and get the best possible performance, or should I go with 243 and take advantage of more bullet options?

If you enjoyed reading about "243 or 270 for short barrels?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
dakotasin
May 16, 2010, 05:23 PM
why do you need velocity and flat trajectory in a brush/med range gun?

between a 243 and 270 for hunting purposes i would take a 270 every time.

floridabou3
May 16, 2010, 05:32 PM
hunting i would take the 243 myself own 2 of them a 7400 and a rem 700 and i love both of them and if im hunting in brush area's take a 30-30. also they say 270 will not shoot hole for hole after the 2 or 3rd shot it gets 2 hot. im sure someone on here that knows more about it can explain it to you better.

Abel
May 16, 2010, 05:53 PM
Varmints/deer under 200 yards ='s 30-30!

Arkansas Paul
May 16, 2010, 05:58 PM
also they say 270 will not shoot hole for hole after the 2 or 3rd shot it gets 2 hot.


I don't see that happening. I don't see how a .270 could be any hotter than any other round with the same powder charge and bullet weight.
I think the OP is trying to have a combination that's hard to get. When you're talking about a varmint round and a brush gun, there's just a lot of room in the middle there. Both calibers you mentioned are great, but the .243 certainly doesn't qualify as a brush gun. Of the two mentioned, I'd go with the .270. You can get round nose soft points for it that are what you want in the brush.

Just one fellers opinion

R.W.Dale
May 16, 2010, 06:29 PM
My research indicates that the 243 and 270 are the two best contenders for highest velocity in a short barrel among the common hunting cartridges.

What gives you this impression?

243 in particular from a carbine is one of the worst possible rifle/caliber combination's. Taking a MASSIVE hit in performance from bbls under 24"

http://www.thehighroad.org/showthread.php?t=510646

If you can wade through the parts where the 243 fanatics call me everything but a THR member for daring to question their cartridges precieved superiority you'll find some very valuable information about just how 243 is put in a straight jacket when fired from a short bbl.

The 30 calibers are out; even though they may have more energy, they also have as much as 50% more drop at longer ranges when fired from a short barrel.


I don't know where you get your info for comparison but it doesn't seem to be grounded in reality. The more overbore 243 and 270 you mention will both take huge hits in the FPS dpt from a carbine compared to the larger bore, higher expansion ratio 30 caliber cartridges

Please elaborate

How short a bbl

and what do you consider long range

jmr40
May 16, 2010, 10:55 PM
Read this

http://www.tacticaloperations.com/SWATbarrel/

If you want a shorter barrel there are plenty of options. I haven't seen any data on the 243, but would think it would benefit from a longer barrel more than most.

I don't have a link to the data results, but recently read of a gunwriter who took a 27" barreled 270 and cut 1" off the barrel at a time and measured velocity loss at each increment until he got to 21". There was a total of 114fps velocity loss. TOTAL.

If you want a shorter barreled gun for hunting the 270 should do just fine, but so would a 308, 30-06 or most anything else.

The guys who want to push cartridges to the limits and shoot at extreme long range need every little bit of advantage they can get. In their case 6-8" more barrel may make a difference. But in a hunting rifle 2"-4" is not worth worrying about.

Grey Morel
May 16, 2010, 10:59 PM
Take it easy Krochus! I am not an expert, and claim no such knowledge. :)

I based my research on generic formulas for velocity reduction per inch, of hot factory loads with a common test barrel length (24").

IE: 2500-3000fps = 20fps per inch, or 3000-3500fps = 30fps per inch.

I realize that these formulas are simply estimates for a wide range of cartridges. That's all I was aiming at was a rough estimate of velocity loss from an 18" barrel. :)

Additionally, this is not a deer rifle, so don't think of "brush rifle" in that sort of application. I consider "long range" to be 400 yards.

bpl
May 16, 2010, 11:37 PM
I think that both .243 and .270 are poor choices for a short barreled rifle. Both depend on high velocity for effectiveness, which in turn depends on adequate barrel length. You'd be better off with 7mm-08 or .308, they do better in a short barrel.

http://www.chuckhawks.com/rifle_barrel.htm

bpl
May 16, 2010, 11:40 PM
Additionally, this is not a deer rifle, so don't think of "brush rifle" in that sort of application.

Sorry, didn't catch this part. What will you be hunting with your "brush rifle", varmints and predators only?

Maverick223
May 16, 2010, 11:46 PM
I think that both .243 and .270 are poor choices for a short barreled rifle. Both depend on high velocity for effectiveness, which in turn depends on adequate barrel length. You'd be better off with 7mm-08 or .308, they do better in a short barrel.Agreed, particularly WRT the 7mm-08. Plenty of energy to kill shrubs and those pesky brush monsters as well as maintaining a fairly flat trajectory for varmints.

:)

don
May 17, 2010, 12:25 AM
Pardon my ignorance, but wouldn't the velocity loss also be a function of the powder used? I mean that wouldn't a .270 or a .243 loaded with a faster burning powder loose less velocity when shot from a short barrel than a slow burning powder?

Maverick223
May 17, 2010, 12:39 AM
Pardon my ignorance, but wouldn't the velocity loss also be a function of the powder used?Sure, but the biggest factor is the case to bore relationship. The larger the case capacity and smaller the bore diameter, the longer the barrel required for efficiency. The inverse being true, a relatively large caliber with a moderately sized case would afford the best performance in short barrel lengths.

:)

don
May 17, 2010, 12:59 AM
Thanks Maverick. What you say makes sense. Just as an academic experiment, It would be interesting to compare the loss rates between say, H4831 and IMR4895 all other factors being held equal.

husker
May 17, 2010, 01:11 AM
I know im A BROKEN RECORD
but a few years back Rem made this rifle called the MOHAWK 600 & they made it in many cals. EVEN 243 & as matter of fact.i think the 243 version sold the most. i dnt call them a brush gun. But my dad did.
i call it a WALKING RIFLE
he had 2 for many years but sold the 243 when he quit hunting deer. the other 1 i still have & EVERY 1 on the THR knows it. :-) & i came DAM close to buying a 600 in 243 when i first joined this great site.
but it just wasn't DADS!!!

Maverick223
May 17, 2010, 01:11 AM
Thanks Maverick. What you say makes sense. Just as an academic experiment, It would be interesting to compare the loss rates between say, H4831 and IMR4895 all other factors being held equal.Glad to be of some assistance. There is a good bit of difference in the burn rate for those two powders. I would hazard to guess that there would be a good bit better burn for the 4895, but the velocity would still be reduced a bit. Heavier projectiles would also result in a small increase in efficiency.

:)

pikid89
May 17, 2010, 11:28 AM
i dont like short barrels but to answer your question straight up...i think the 243 would be better suited to a short barrel for its faster burn rather than the 270....

i came across the same debate in regards to the ruger international (18.5" bbl) in 308 or 30/06 and the 308 seemed to be the better choice because the 3006 had a slower powder=less velocity+more fireball

SlamFire1
May 17, 2010, 11:48 AM
I don't remember the barrel length, whether it was 20" or 22" in my 243 M70 featherweight, but I do recall I was not impressed with 2830 fps with a 100 grain bullet.



243 M70 Featherweight Classic



100 grain BT Spire Point Hornady Factory Ammo
26 Jun 01 T=84 F

Ave Vel = 2830
Std Dev = 17
ES = 79
Low = 2803
High = 2882
N = 18

kludge
May 17, 2010, 01:03 PM
6.5x55, .7mm-08, .260 Rem.

No lack of good bullets, velocity, flat trajectory or energy, out to 300 yards and perhaps more for varmint up to deer. All would work fine with a shorter barrel.

Ridgerunner665
May 17, 2010, 01:05 PM
The 308 Winchester is best suited to the OP's task...

R.W.Dale
May 17, 2010, 01:14 PM
The 308 Winchester is best suited to the OP's task...
A agree and the cartridges the OP mentions are some of the least suitable to the task he outlines.

With regard to 270 and 243 they both suffer from the same problem small/medium bore belted magnums do in that they take a long bbl to reach their full potential.

Grey Morel
May 17, 2010, 08:14 PM
I think that both .243 and .270 are poor choices for a short barreled rifle. Both depend on high velocity for effectiveness, which in turn depends on adequate barrel length. You'd be better off with 7mm-08 or .308, they do better in a short barrel.

http://www.chuckhawks.com/rifle_barrel.htm

Funny you bring that up. HIS formulas were the ones that I used to calculate velocity loss. ;)

I suppose I could warm up to a 30-06 for ammo commonality reasons. Would that be a better performer?

Ridgerunner665
May 17, 2010, 08:38 PM
No it wouldn't...a short barreled 30-06 is nothing more than a 308 that wastes a lot of powder.

There a chosen few rounds that do well in shorter barrels...and the 308 is at the top of the heap (the rest being the 30-30, 35 Rem and such)

In order to get the good out of a short barrel...you need a round with a small case capacity No long action caliber meets that requirement.

The problem with the 243 is a tad different...it would seem to have a small case capacity, but it only seems that way. For those small 6mm bullets...it has a rather large case capacity...so you're right back to square 1.

Short barrel requirements (medium bore, medium capacity rounds)

The 243 will lose 100 fps per inch below 22 inches (with 100 grain bullets)...I know, i have a 20" 243.

The next best thing to the 308 I believe would be a 257 Roberts...it would lose a lot, but not as much as a 243.

PedalBiker
May 17, 2010, 10:12 PM
The Hodgdon annual reloading manual has a lot of reloading data for rifle cartridges in 14" barrel handguns. The exact same load data is shown in the rifle section for 24" barrels. That can give you a good feel for short barrel performance.

The 243 and 270 are in both sections. Check it out, slow powders don't take the hit I expected they would.

Abel
May 17, 2010, 11:07 PM
Believe it or not, you're right back to the 30-30! In an 18.5"-20" barrel, its efficient. Consider the Ruger Compact in 6.8mmSPC.

dakotasin
May 18, 2010, 01:29 AM
I haven't seen any data on the 243, but would think it would benefit from a longer barrel more than most.



The 243 will lose 100 fps per inch below 22 inches (with 100 grain bullets)...

my apologies for trotting this link back out to those that have seen it, but i think this discussion warrants it - it is a link to some chrony data i did w/ a 243 in a 16.5" barrel and a 26" barrel: www.baitshopboyz.com/forum/forum_posts.asp?TID=18089&PN=3 if you read the link you'll note velocity per inch using same lot# factory ammo equates to around 35 f/s/inch between a 16.5" barrel and a 26" barrel depending on specifics.

I don't have a link to the data results, but recently read of a gunwriter who took a 27" barreled 270 and cut 1" off the barrel at a time and measured velocity loss at each increment until he got to 21". There was a total of 114fps velocity loss. TOTAL.

probably a charlie sisk experiment. he did it w/ a number of chamberings. his thesis was that whatever velocity you lose you can mitigate by going w/ a faster or different powder combination. his findings were interesting, indeed, and especially relevant because it was the same barrel being used. however, the theory was somewhat of a myth, but it did work quite well in some examples.

to that end, i conducted an experiment of my own w/ an 8x57 mauser. starting w/ a 29" barrel and worked it down to 16" or so in various increments. my findings were that velocity loss in the 8x57 wasn't much, and i would say that was probably a function of the relatively low powder charge in relation to bore diameter (the custom 8x57 i had built sports a 17" barrel if that's any indicator). i have also run an experiment w/ a 7 rem mag from 26" to 21" and found there to be a pretty significant drop in velocity once you dropped to about 23" or shorter (the custom 7 rem mag that i should have back in a couple weeks is 26"). and as long as the subject is there... i also tried the david tubb abrasive bullet trick to see if it worked as advertised in increasing velocity and accuracy in the 8x57... it did not.

for whatever it is worth... i have done pretty extensive hand load work for both the 243 and 270 (i own examples of each), and neither is a cartridge i find particularly good in a short barrel. however, i still think a 270 is better than a 243 in any given non-varminter hunting rifle scenario. i also think the op would be very well served to go up in bore size and take a serious look at the 308 win or at least a 308 win based case larger than 257 cal (and i think the world of the 25 souper, but not in this application).

Art Eatman
May 18, 2010, 11:08 AM
My .243 is a Sako Forester carbine; 19" barrel. At 7 pounds ready to hunt, it's certainly "light and handy".

I've tagged over 20 bucks with it, plus a culling program. Sierra 85-grain HPBTs.

It wears an old Leupold 2x7 scope, which I've found is plenty-nuff for prairie dogs to 300 yards with 55-grain handloads.

Overall, sub-MOA groups, always--except with 100-grain Noslers. Probably, a bit too slow in the twist rate for the length of the bullet.

AH-1
May 18, 2010, 10:07 PM
y'all listen to art eatman.he knows what he is talking about.

I have never read so much bs in one thread in my life:).
in over 40 years of hunting I have only killed 2 deer over 100 yards but that said I am a hunter get close and make the shot count.

pete

Grey Morel
May 28, 2010, 05:08 PM
Thank you all again for your input. Let me see if I'm making proper sence of both sides:

One side of the argument is that velocity loss is a function of powder to bore size, so something like a 30-06 or 308 would function much closer to advetised velocity.

The other side of the argument concedes the velocty loss but holds that the entire issue is a moot point because cartridges like 243 still maintain plenty of killing power at practical distances, regardless of the loss is velocity.

It seems like I've asked one question, only to be given two more to ponder. :)

bpl
May 28, 2010, 08:09 PM
Since this gun will pull double duty as short to medium range varmint gun, as well as a brush gun, I'm focusing on high muzzle velocity and flat trajectories rather than muzzle energy.

was aiming at was a rough estimate of velocity loss from an 18" barrel.

Additionally, this is not a deer rifle, so don't think of "brush rifle" in that sort of application.

So, are you looking for a short-barreled varmint/predator rifle??? If so, why not just go with the .223? It'll do fine out of an 18" barrel for the purpose of killing varmints.

Grey Morel
May 28, 2010, 09:42 PM
We can't hunt deer with rifles here.

Plenty of other things that need killing in close cover though, and rifles are what I know best.

Justin Holder
May 29, 2010, 12:25 AM
Just go with the 243 and don't look back. It is better suited to predators and such, also less recoil and muzzle blast than 270.

Velocity according to Hornady

243 100gr 24'' - 3000 fps
243 100gr 15'' - 2600 fps

270 130gr 24'' - 3100 fps
270 130gr 15'' - 2700 fps

Both loose about 400 fps

Art Eatman
May 29, 2010, 09:44 AM
For prairie dog type varminting, the .243 will be bunches better: Your shoulder will tell you so. A hundred rounds of .270 is not a thing of beauty and a joy forever. Of course, for coyote type varminting, it doesn't matter. One or three shots a day, most likely.

Inside of 200 yards on Bambi? Might's well choose less recoil there, as well. The "killing power" is equal, for all practical purposes.

IMO, the .270 is a great cartridge for hunting medium sized game in rather wide-open country, which is what I used mine for.

Fremmer
May 29, 2010, 10:12 AM
I don't think it'll make much difference which caliber you choose. Both will lose velocity as you shorten the barrel, proportionate to the weight of the bullet you shoot (I suppose the .270 can hold more powder, but I don't think it'll make too much difference, I'll let the handloaders talk about that). I wouldn't worry so much about comparing trajectory and stuff like that from a shorter barreled gun, especially one used in brush. But even for the long-range shots, if you practice enough with it, you'll learn the drop just fine. So it probably doesn't matter so much which caliber you choose.

Funny, you could say one one hand, the .270 is worse for long shots because of drop from a heavier bullet, but on the other hand, the .270 is better because the heavier round bucks the wind better. :D

I'd probably go with the .243 just because I'd expect it to be a tad quieter than the .270 from a short barrel. But that's just because of a sensitive right ear.

Abel
May 29, 2010, 10:31 AM
I think the 6.8SPC (270 Bantam) is designed around use in a short barrel.

pmeisel
May 29, 2010, 01:10 PM
Art is right on as usual, the 243 will do varmints much better than a 270 and deer plenty well enough.

You would not enjoy shooting dozens of 270 in a day, I don't think... It is a fine round but more than you would want to shoot all afternoon.

nathan
May 29, 2010, 01:13 PM
My Remington 700 Youth model .243 has a 20 inch barrel. I love it s compactness but i really wish it was in 22 inch barrel .

Maverick223
May 29, 2010, 01:17 PM
Why not just go with the .270Wby, or better yet a 7mmRUM?

Why would anyone want to go with something like a 7mm-08Rem. or 6.8SPC...I mean who cares that they will have near the same velocity and energy at much less cost, recoil, noise, blast, weight, and in a shorter action? :rolleyes:

Rokman
May 29, 2010, 03:46 PM
I agree with Abel. I would love to have a 6.8SPC carbine bolt action. I have a 22" Winchester .270 featherlight. I also have a Ruger Compact 77MKII with a 21.5" barrel in .30-06. I feel that neither one of these give up much to thier longer barreled relatives.

Abel
May 29, 2010, 04:02 PM
I would love to have a 6.8SPC carbine bolt action.

http://www.ruger.com/products/m77HawkeyeCompact/models.html

Rokman
May 29, 2010, 06:27 PM
Abel, I really like that Ruger, but the twist is too fast. It would be a handy little sucker.

Abel
May 30, 2010, 12:36 AM
What weight bullets do you want Rokman?

Rokman
May 30, 2010, 01:03 AM
I shoot 110 grain Sierra Prohunters and 115 grain Sierra Matchking bullets in my AR. It appears that all the twist rates are moving to 1:11-1:12 these days, with specII chambers, or at least in the ARs that what it seems.

Dallas Jack
May 30, 2010, 08:13 AM
I once owned a Model 7 Remington in .243 (18.5 inch barrel). It was a great shooting rifle as well as being short and light. Very handy for carrying around in the woods.

Both the .243 and .270 benefit from a longer barrel but neither turn to crap when used in a shorter barrel.

The .243 also has the advantage of being a short action cartridge.

As for the cartridges themselves I allways concidered the .243 to start at varmints and got up to whitetails, antelope, mule deer, black bear. I feel the .270's range to start at whitetails, antelope, elk, sheep, goats, and large black bear. And of cours either will work dandy on ferals pigs,bobcat,and foxs with a bias toward the .243

If I were th OP I would find the gun that fit and handled the best and then select the cartridge. A .250 savage or .260 remingtom may catch his fancy.:)
Dallas Jack

Abel
May 30, 2010, 09:37 AM
I would think that the 1:9.5 would shoot the 115's fine if that's what Ruger put on it. In other words, there isn't any factory 130's out there. Why would Ruger make the rifle for anything but the 115's?

Rokman
May 30, 2010, 10:40 AM
Abel:

I don't want to take away too much from the original pupose of this thread, but I think the compact Ruger would be a dandy in 6.8SPC. I handload the 6.8 pretty hot in my Spec II chambered AR and the slower twist and less grooves in the barrel is supposed to lower pressure and help with hot load such as Silver State Armory loads.

Grey Morel
May 30, 2010, 11:45 AM
If I were the OP I would find the gun that fit and handled the best and then select the cartridge.

'aint my first bite at the apple, friend. :)

The rifle I want is only available in 243, 270, 308, and 3006. I don't own any rifles in any of those calibers, so the only issue is which cartridge will give me the best performance.

Rokman
May 30, 2010, 12:05 PM
Grey, they are all good. Don't think that you could go wrong with any. I don't have a rifle in .243, but I do have a .22-250 and a .25-06, so I never thought that I needed to bridge the gap so to speak. In my opinion, they are all pretty flexible cartridges if you want to handload for special bullet weights and they are all easy to purchase factory ammo for.

Maverick223
May 30, 2010, 10:16 PM
The rifle I want is only available in 243, 270, 308, and 3006. I don't own any rifles in any of those calibers, so the only issue is which cartridge will give me the best performance.The .308Win. would offer hands down the best efficiency (of course the .30-06 would offer slightly more energy, but have more disadvantages due to the lesser efficiency), and fit the carbine much better IMO. If I were dead set on that particular rifle, the .308Win. would be my only consideration.

:)

Art Eatman
May 30, 2010, 11:28 PM
"Since this gun will pull double duty as short to medium range varmint gun, as well as a brush gun..."

Maverick223, since that's the purpose of the OP, are you really sure you'd want a .308 or an '06 as a varmint gun? :D

Figure a fella will get two or four shots a year on Bambi. Even for "just coyotes" instead of prairie dogs, he'll get a lot more shots. Why beat on your shoulder? :)

Maverick223
May 30, 2010, 11:45 PM
Maverick223, since that's the purpose of the OP, are you really sure you'd want a .308 or an '06 as a varmint gun?Nope, but I wouldn't want a carbine length rifle for that task either (due to blast, noise, and loss of efficiency). He asked which one afforded the best performance, and that is either the .308 or '06 depending upon our definition of performance. I figured he was talking about efficiency, so I answered....308Win. If it were energy the answer would be .30-06 instead. FWIW, I think the .260Rem. or .223Rem. fits his needs best (but not ideally by any stretch), but neither are offered in his chosen carbine so that is a beside the point.

:)

Lloyd Smale
May 31, 2010, 08:55 AM
Ive killed quite a few deer with the 243/6mm in barrel lenghts from 18 to 24 and ive yet to see a bullet bounce off a deer because it came from a 18 inch barrel. As a matter of fact i doubt your ever going to notice a differnce in killing power out to 300 yards. A 243 with a 100 grain bullet can easily run 2800 fps and thats as fast as most 06 factory loads will run out of a 22 inch barrel so its darned near as flat shooting. A long barrel isnt a bad choise for open country hunting but in a thick area where shots are seldom out past a 100 yards the extra velocity can actually be detrimental to bullet performace. Hard to get an exit wound with a 243 running 3000fps when the animal is only 50 yards out. As to the 308 3006 debate. Dont let anyone tell you that because your using a 2o inch barrel there equal. Id bet you a dime to a dollar i can push a 150 out of an o6 faster in a 20 inch barrel then your going to get a 308 up to out of a 22. Make that bullet a 165 or 180 and the o6 will open up the spread even more. You need to keep in mind that when comparing the two that factory 308 is loaded to higher pressures the the 06 and thats what keeps them close. Load both to the same pressure and the o6 will pretty much stomp on the 308. Dont get me wrong i love the 308 too. It just goes back to the fact it again is about a 2800 fps round and theres nothing wrong with that and it allows for a short action which makes for an even lighter shorter handier gun. A 308 is no more equal to an 06 then the 06 is to a 300 mag. As to a little more muzzle blast thats not much of an argument. I wear ear plugs at the range and bottom line is in the field shooting one or two shots without them i doubt its going to mean the differnce in you going deaf or not. I know a few guys that just have to have 26 inch barrels and load there guns well above book pressures thinking there really accomplishing something. Me im just the oposite. Rarely do i run a gun at the absolute max. If my 308 isnt enough for the job at hand i grab a 06 if thats not good enough then i grab a 300 mag. One of my favorite deer rifles and a gun thats accounted for a truck load of deer is a ruger international 250-3000 and its pet load is a 120 nos solid base or a 117 sierra loaded to just over 2500 fps. Ive shot deer out to 250 yards with that combo and have yet needed to track a wounded animal. It has been used by everyone at camp and has aquired the nickname thor because most deer shot with it drop like hit with the hammer of thor. Its nothing majical and certainly less gun then alot of guys would recomend but it works and its almost as handy as a 94 in the thick stuff.

Dallas Jack
May 31, 2010, 08:02 PM
A simple answer, if you want to shoot lighter bullets (55 to 105 grains) then .243. If you prefer a little heavier bullets (100 to 150 grains then .270.

My preference is the .243.
Dallas Jack

Ridgerunner665
May 31, 2010, 08:25 PM
Somebody up there said the 243 didn't lose 100 fps per inch below 22 inches...

That may be your experience, but it wasn't mine...trying to shoot 100 grain bullets from a 20" barrel (Remington youth model) mine is pathetic...literally pathetic.

It did lose 200 fps compared to a 22" barrel (another Remington...an older one with many rounds down the tube) with the same loads...tried different powders, settled on a compressed charge of Reloder 19.

I know no 2 barrels are alike...but this has came out the same way on a couple other 243's I know of.

jmr40
May 31, 2010, 09:00 PM
Ridgerunner, I've done a LOT of reading on the subject and have never seen an example where 1" of barrel length made 100 fps difference. I have read of 2 different guns with the same barrel length haveing 100 fps difference. There are numerous articles written where people have started with long barrels and gradually cut them off 1" at a time and measure velocity.

The trend I've noticed, regardless of the round, is that the difference in the first few inches is very minimal. Going from 28" down to 22" may only result in 10-15 fps velocity loss for each inch of barrel.

At some point you reach a length where you do suddenly see a large drop off. For example the difference between 22" and 21" may well see 50fps loss. This trend may continue for 2-3 inches then you go back to only 10-15 fps for each inch.

To say that a given cartridge looses a certain velocity loss per inch can be very misleading. Many people will observe the 50 fps of velocity loss between 22" and 21" and assume that trend continues for each and every inch. Others may only observe only 15fps loss between 18" and 19" and assume the same.

The only thing I can assume is that it is not an exact science. And is far less important in the real world of hunting. 200 fps either way is not that big of a deal in a hunting rifle at typical hunting ranges. For the guys target shooting at 1,000 yards, or the guys who want to shoot deer at 600 yards it may matter. But those guys are not asking for advice here.

Ridgerunner665
June 1, 2010, 12:00 AM
I haven't done much reading on it...just my own load development.

And from that, I've seen that much of what I have read is wrong. Mainly due to blanket statements of 35-50 fps.

Short barrel performance is very dependent on case capacity to bore ratio (or over bore if you wanna call it that)...and some rounds have shown to be very fussy with it.


200 fps may or may not be a big deal...depends on the application.

I don't expect to change anybody's mind...I'm just stating what I've seen.

Grey Morel
June 1, 2010, 12:12 AM
Here the main varmints are Coyotes and Muskrats. Neither one are very tasty, or worth anything as pelts. We have ways of dealing with them:

Coyotes: A war of attrition. Application of dynamite to suspected dens in not considered uncalled for.

Muskrats: These cause so much damage to local irrigation, that it not only damages crops, but causes machinery to be lost when portions of undermined fields collapse. The standard method of disposal is to shoot them in the water with a large caliber weapon: this often results is spectacular displays of aerial acrobatics on the part of the muskrat.

So... no I don't personally consider 30-06 to be too much for varmints. It sure is fun to see those muskrats fly. :)

R.W.Dale
June 1, 2010, 12:21 AM
I haven't done much reading on it...just my own load development.

And from that, I've seen that much of what I have read is wrong. Mainly due to blanket statements of 35-50 fps.

Short barrel performance is very dependent on case capacity to bore ratio (or over bore if you wanna call it that)...and some rounds have shown to be very fussy with it.


200 fps may or may not be a big deal...depends on the application.

I don't expect to change anybody's mind...I'm just stating what I've seen.

JUST TO BACK UP THIS STATEMENT

100g Remington 243 loads I chronographed from a 788 carbine (18.5"IIRC) averaged a mere @ 2674 FPS

Grey Morel
June 1, 2010, 01:25 AM
From what I'm hearing, I think I will probably go with the 30-06. I appreciate everyone's input, and the lively debate. :)

Ridgerunner665
June 1, 2010, 02:33 AM
Krochus,

I didn't quite get that much speed from my youth model with a 20" barrel...compressed Reloder 19 till it crunched, and I got 2,608 fps.

Those ole 788's have better barrels though...

Edited to add: Same load in a 24 inch barrel chrono'd 3,060 fps.

R.W.Dale
June 1, 2010, 02:52 AM
Krochus,

I didn't quite get that much speed from my youth model with a 20" barrel...compressed Reloder 19 till it crunched, and I got 2,608 fps.

Those ole 788's have better barrels though...

Edited to add: Same load in a 24 inch barrel chrono'd 3,060 fps.
I only had the factory ammo spec to compare to so IMO your tests are a bit more conclusive.

Either way i think what the op should take away from our posts is that a 243 carbine is little more than a really loud 30-30 in terms of power and to a certain extent external ballistics.


while not what it's intended for the below chart reads like a list of best to worst performers in a carbine barrel

http://accurateshooter.net/Blog/overborechart4a.png

Ridgerunner665
June 1, 2010, 02:54 AM
Yep...good post.

That chart says it all for short barrels.

R.W.Dale
June 1, 2010, 02:58 AM
I should also point out that even though I don't have the hard numbers on a 270 carbine by the math it should perform almost as poorly from a short tube as 243

Ridgerunner665
June 1, 2010, 03:01 AM
I haven't worked with a short 270...but I believe you are correct.

I noticed he said he was gonna get a 30-06...he may as well get a 308 because thats all a 20" 30-06 is (a 308 that wastes a lot of powder, with a HUGE muzzle flash)

R.W.Dale
June 1, 2010, 03:07 AM
A quick view of hodgdon's handgun data for 308 vs 30-06 really tells the story of how 308's higher pressure rating and lower expansion ratio really help it edge out the 06 in a carbine barrel. Again see the chart


An easy way to relate to the handicap with a carbine vs rifle 243 (using our figures in any ballistics calculator) is that when using a short barrel you're effectively making every shot you take a 100yds farther away than it really is

Ridgerunner665
June 1, 2010, 03:13 AM
I'm gonna say this just to qualify what I've said here...


I HATE long barrels...I have spent a pretty fair sum of money and time finding what works in shorter barrels. If one were to search back through all my posts they would see that most of my shooting has been with 2 calibers. Believe me, I have no shortage of guns to choose from, yet I do my hunting with either a 308 or a 45-70. There is a reason I ended up with those 2 calibers...

I won't carry a gun with a 24" barrel...and I don't like rounds that give up all their benefits when fired in a short barrel.

I am FAR from an expert on much of anything...but I have put a lot of effort into this, I didn't read it in a magazine or on the internet.

Ridgerunner665
June 1, 2010, 03:16 AM
A quick view of hodgdon's handgun data for 308 vs 30-06 really tells the story of how 308's higher pressure rating and lower expansion ratio really help it edge out the 06 in a carbine barrel

Yep...and Sierra's reloading manual will back that up (compare rifle to handgun...they list those calibers as well)

Ridgerunner665
June 1, 2010, 03:33 AM
I just looked over Hodgdens pistol data...actually the 30-06 and 308 are identical in velocity pretty much across the board (bullet weights).

I don't have the Sierra manual in front of me, but IIRC in Sierra's manual the 308 was slightly ahead of the 30-06.

That doesn't really surprise me though...Sierra is VERY conservative in their load data, Hodgden is not...they will load it right up there.

R.W.Dale
June 1, 2010, 03:42 AM
Right!

From a rifle 30/06 has appx 100 fps on 308 with like weight bullets. Untill you shorten the bbl at which point this advantage disappears. In other words a short barreled 06 is simply a 308 that burns more powder

Maverick223
June 1, 2010, 01:09 PM
From a rifle 30/06 has appx 100 fps on 308 with like weight bullets. Untill you shorten the bbl at which point this advantage disappears. In other words a short barreled 06 is simply a 308 that burns more powderYes sir, you guys are on the right track. And this is coming from someone that greatly prefers the .30-06 to the .308Win. in most cases, and like other cartridges (like the .260Rem. and .280Rem.) better than both for the most part. You also have to factor in the fact that the .30-06 generally uses slower powder than the .308, which at least theoretically (or in the Sierra manual) could lead to the .308 being faster. :eek:

jmr40
June 1, 2010, 01:28 PM
I've got to disagree that a short barreled 30-06 is only a 308. For one thing that statement is almost true even if both barrels are the same length.

Take a 300 mag, 30-06 and 308 all shooting the same bullet. With equal barrel lengths the 300 will always be the fastest and the 308 will always be the slowest with the '06 in the middle. It does not matter if the barrels are 30" long or 16".

R.W.Dale
June 1, 2010, 01:43 PM
It does not matter if the barrels are 30" long or 16".

but that's just it. It does matter, a great deal in fact.

A 300wm will indeed pick up a greater boost in velocity from a 30" bbl vs 24" than 308 and 30-06 will and on the flip side 308 will lose less velocity from a 16" barrel than 30-06 or 300wm does. According to the numbers at some point around 16" or less the higher pressure more efficient round (308) actually begins to leave the muzzle traveling faster than the 30-06

Look at it this way the higher the bore case capacity is the longer the barrel needs to be to allow time for all that high pressure gas in the chamber to get out that little hole in the end and actually push on the base of the bullet

Maverick223
June 1, 2010, 01:59 PM
but that's just it. It does matter, a great deal in fact.

A 300wm will indeed pick up a greater boost in velocity from a 30" bbl vs 24" than 308 and 30-06 will and on the flip side 308 will lose less velocity from a 16" barrel than 30-06 or 300wm does. According to the numbers at some point around 16" or less the higher pressure more efficient round (308) actually begins to leave the muzzle traveling faster than the 30-06

Look at it this way the higher the bore case capacity is the longer the barrel needs to be to allow time for all that high pressure gas in the chamber to get out that little hole in the end and actually push on the base of the bullet+1; this is an exaggerated situation, but a .308Win. would almost certainly outclass a .300WM in a sub-12in. bbl (and likely a longer one) due mostly to the powder designed to burn slowly and keep up pressure throughout a relatively lengthy barrel.

:)

Ridgerunner665
June 1, 2010, 04:59 PM
I've got to disagree that a short barreled 30-06 is only a 308. For one thing that statement is almost true even if both barrels are the same length.

Take a 300 mag, 30-06 and 308 all shooting the same bullet. With equal barrel lengths the 300 will always be the fastest and the 308 will always be the slowest with the '06 in the middle. It does not matter if the barrels are 30" long or 16".

With all due respect...you are leaving out one VERY important aspect.

And that aspect is the "time" it takes to burn the powder...the more powder, the more time it takes. And that time is referred to as "barrel time" (the length of time the bullet is in the barrel after firing).

Short barrel, magnum powder charge = powder blown out the muzzle, some still burning...some unburned. (unburned = loss of velocity)

Oh...and a 20 inch 300 Win Mag, can be exceeded by a hot 30-06 load from a 24" barrel.

Grey Morel
June 2, 2010, 12:00 AM
Nice Chart. Could come in handy later.

AH-1
June 2, 2010, 12:41 AM
http://www.shootingtimes.co.uk/features/136776/How_important_is_the_barrel_length_of_a_rifle.html

Legionnaire
June 2, 2010, 11:21 AM
Good thread; not much I can add. I have Remington Model 7s in both .243 and .308. I've been playing around some with load development, and thus far can add the following observation: Much easier to approach published velocities with the .308 than the .243 in the 7s' shorter barrels. Don't have my notes in front of me, or I could add specific velocities. But no doubt the .243 is giving up a significant amount in the shorter barrel using the 100 grain PSPs I've been using.

And to the OP's original question, I'd still opt for the .243 over the .308 for varmints at reasonable ranges.

Legionnaire
June 4, 2010, 12:40 PM
I've been thinking about this thread since reading it a couple of days ago. Something was nagging, and that was a sense that the overbore table in krochus' post seemed to be missing something. I'm not a physicist and am only a relatively new reloader. But it seemed to me that the table leaves out some important variables: notably powder bulk and energy (burn rate) and bullet weight. So I did some additional digging on the web and came up with the link below:

http://ninthstage.com/index.php/2008/05/06/overbore/

I'd be interested to hear what some of you others think about the arguments made there. Regardless, I'm thinking that the key shooting .243 Win cartridges in short barrels is to custom build your ammo to the task. I think I suspected this because of knowing that there are special reloading data for T/C Contenders and Encores, with their shorter barrels. Thoughts?

R.W.Dale
June 4, 2010, 01:16 PM
You're putting the chicken before the egg.

My chart does not leave out burnrate because that is completely dictated by bore case ratio and bullet weight. Barrel length is irrelevant. Just look at the cited hodgdon data and you'll note that the top performing propellants are by in large also the top performers in a handgun.

Why is this? It's because guns unlike rockets don't rely on thrust from a continuously burning fuel source. Folks think burn rate is linear with bullet travel down the entire length of the bbl. This is false. But rather burn rate really just relates to the first couple of inches of bullet travel after which the powder is all consumed (that can burn) and pressure is dropping rapidly as the volume in the bore/chamber increses.

To get the highest velocity possible with any given cartridge you want to burn the largest quantity of the slowest propellant (most energy) that the cartridge can just reach max pressure with. Using a lesser quantity of a faster powder will ALWAYS result in a lower MV in all bbl lengths is the same pressure levels are maintained

a very informative discussion we had on this
http://www.thehighroad.org/showthread.php?t=498504&highlight=powder+fast

Legionnaire
June 4, 2010, 02:11 PM
I hear you, but am still wrapping my head around it. I understand that burn rate is not linear, and that there is a peak pressure. But "fast" versus "slow" powders peak at different times, don't they? Don't you want the curve to peak just prior to the projectile leaving the barrel? In the other thread, you said that using a "faster than optimum powder will not provide more velocity in a shorter barrel ..." suggesting that there IS an "optimum." No doubt I'm missing something.

R.W.Dale
June 4, 2010, 02:20 PM
Don't you want the curve to peak just prior to the projectile leaving the barrel? No doubt I'm missing something.

From what Ive seen generally speaking pressure peaks right as the bullet hits the rifling or thereabouts. After that point gas pressure is dropping off rapidly because the space inside the bbl it has to fill is increasing as the bullet travels. pressures at the muzzle are a mere fraction of what they were at the chamber.

RcModel has an excellent post here that explains this relationship
http://www.thehighroad.org/showpost.php?p=5974432&postcount=5

Folks get hung up because they relate powder burn to the entire bbl length. When in reality it just relates to that first couple inches before the bullet has a chance to start "getting out of the way"

Legionnaire
June 4, 2010, 02:27 PM
Appreciate your patience ... think I'm almost there. So, in a nutshell, what makes a powder "too fast" or "too slow?" Weight of the projectile?

R.W.Dale
June 4, 2010, 02:37 PM
Amongst a few other things. Remember the bore is a set size so that effects how the pressure drops (through expanding volume) in relation to how it builds from the burnt propellant.

a gross over simplification

Too fast a propellant in relation to the bullet weight, bore size and case capacity and the pressure can spike before moving the bullet uncovers sufficient volume to keep pressure in check.

Too slow a propellant and the bullet and therefore expanding volume outruns the powders ability to turn to gas resulting in low pressures and MV's

The important thing to take from this is that all this occurs just as the bullet starts moving

Legionnaire
June 4, 2010, 02:55 PM
Thanks! Very helpful! If I understand ...

Too fast a propellant in relation to the bullet weight, bore size and case capacity and the pressure can spike before moving the bullet uncovers sufficient volume to keep pressure in check ... ... with potentially cataclysmic consequences because the pressure has to go somewhere. And as you note, too slow can reduce pressure and velocity.

Again, many thanks.

Art Eatman
June 4, 2010, 03:18 PM
Somewhere on the Inet is a bunch of graphs of pressure curves for rifles. Been a good number through the years in some of the gunzines. My memory has it that that the peak pressures for rifles seem to occur about one-third of the way through the time of burning--or a probably-standard sort of barrel length, whatever. (The curve won't vary with length, of course, but most barrels are in the 22"-24" range, SFAIK.)

Legionnaire, a generality would be that slower powders require longer barrels for maximum effectiveness. This is particularly true with overbore cartridges. Anyhow, the peak pressure isn't higher; it's that the powder burns longer. More area under the pressure curve.

Fast burn powders work for small "underbore" cartridges such as the .22 Hornet. In my ignorance, I'd think that the Hornet wouldn't gain much from barrels beyond 18 to 20 inches. OTOH, an '06 does very well with barrels of 26" when using slower-burn powders; even 30" barrels for the Very Long Distance shooters.

Grey Morel
June 6, 2010, 01:09 AM
I have a question for Krochus:

How does one determine the "optimum" case capacity for a given bore? Is there some kind of formula? If so is said formula based on empirical data, or the ever popular gun writer style wild guess ? Or is it more of a popular consensus / estimation?

R.W.Dale
June 6, 2010, 01:19 AM
WAG time

I would say it has most to do with the kind of ballistic performance you expect vs the sacrifices you're willing to make. If you shoot 1000yds + your probably a bit more ameiable to burning some extra powder through a long barrel that may wear out faster.

The guy shooting Bambi or steel 75 yds away will likely select a cartridge a that's a bit more fuel efficent that does better in his carbine lenght bbl.


That's why this thread got so hot. The OP's cartridge selection really didn't fit the intended use that well.

jmr40
June 6, 2010, 08:19 AM
Been away for about a week and have not had a chance to respond to the posts on page 3. Will be away for about another week so I won't have a chance to respond again for a while.

You can play around with theoretical math equations all you want. I've seen the chronograph numbers on too many rifles.

There is never a time when a 308 will be faster than the 300 wm. I have never seen a barrel length where a 308 was faster than a 30-06 when they are shot from the same length barrel.

If you WANT a shorter barrel you can make a good argument that the bigger round is the better choice. It may lose a larger percentage of it's velocity, but because it starts faster, it will still be faster even from a shorter barrel. Yes, a 308 is more efficent than a 30-06. The 30-06 may have a 200 fps advantage when both are shot from a 24" barrrel. Go to a 20" barrel in both rifles and the 30-06 will still be faster. Possibly by only 180 fps now. Some of you are over thinking this.

A few other myths.

A powder and load combination that gives the fastest velocity from a long barrel will still be the fastest from a shorter barrel. There is no reason to go to a faster burning powder because you have a shorter than standard barrel length. All the powder, will burn within the first few inches no matter how fast or slow. The longer barrels allow more time for the pressure to increase, thus increasing velocity. I know this is hard for some to accept, but once again I've seen the chronograph results too many times.

Velocity loss is not linear. Most guns do just fine in barrels from 20"-24". With most guns you will probably see the biggest velocity losses/gains between 20" and 24". You can make a good argument that if you are going to go 20", you may as well drop down to the legal minimum of 16" since the velocity loss between 20" and 16" will likely be far less than what you lost between 24" and 20". Same thing if going longer. The gains in velocity will be less and less for each inch you gain over 24".

For a hunting rifle, in any caliber, select the barrel length that feels best to you and stop worrying about velocity. Even if you do lose 200 fps between a 24" barrel and a 20" barrel there is not a game animal in the world that will know the difference when you shoot it. If a bullet at 2900 fps is adequate the same bullet at 2700 fps, even 2500 fps, is not suddenly going to bounce off the hide. At 200-300 yards the trajectory is close enough to not matter, and at longer range we are talking about only 2-3" more drop.

Grey Morel
June 6, 2010, 11:40 AM
Thanks Krochus, I had a feeling that it was more of a popular opinion that an actual fact. Either way it still interests me greatly, as I am firmly in the efficiency camp.

The 30 calibers may be more efficient for use in the rifle I originally envisioned, but the more I think about it the more it seems I need to pick a better rifle for the task.

Thanks again to everyone for the help, and the lively debate. :)

Fremmer
June 6, 2010, 11:47 AM
burn rate really just relates to the first couple of inches of bullet travel after which the powder is all consumed (that can burn) and pressure is dropping rapidly as the volume in the bore/chamber increses.

Yeah, I've been thinking Legionnaire's point for the last couple of days, too. There would seem to be variables that aren't accounted for in the chart (although the chart really isn't being advocated as a specific answer to the OP's question but, rather, as a general guide regarding case size, bore size, and a general correlation between the two concerning velocity. Legionnaire is thinking more about how different powders might burn (outside of the general overbore/slower burning powder point made by Art), as well as other possible variables like barrel vibration caused by different barrel length, etc..... But we could get ultra nit-picky about a million different variables, couldn't we? :D

The OP needs two rifles. One for varmints/targets, and one for deer/targets. How's that for a solution? :neener:

Red State
June 6, 2010, 11:57 AM
jmr40,

Yes, I think you are right in that velocity loss is not linear. But I think you miss-wrote?
The .308 gains quite a bit of velocity when going from a 16" barrel to an 18" barrel. Way more of a gain than when going from a 20" to a 22".

Maverick223
June 6, 2010, 01:56 PM
There is never a time when a 308 will be faster than the 300 wm.Yes there is, if the powder burn is not complete (it is not always or even often in the first few inches) then you are pushing unburned powder out the muzzle along with the bullet. It is essentially unused mass, and this additional unwanted mass slows the projectile. Add in the fact that slower burning powder is used for magnum cartridges and this accelerates the deterioration in velocity from magnum cartridges.

:)

recurry
June 6, 2010, 07:44 PM
Hi Grey,

I'm not big into ballistics so can't help with the technical particulars of velocity loss, etc. with various barrel lengths. However, I can't stand long barrels, so I don't own anything with more than a 20" barrel on it. From my own experience hunting coyotes, the barrel length really doesn't matter. I'd be more concerned with accuracy than the miniscule differences in FPS/LBS between different barrel lengths in either of those calibers.

That said, I'd go with the .243 if I were you, simply because it's a much cooler round to play with - so many options in terms of bullet weights, etc. Not to mention the fact it will be easier on your shoulder and more fun to shoot if you are hunting prairie dogs or just plinking around on a weekend with it. I don't think I'd enjoy walking around plinking at rabbits or prairie dogs with a .270 all that much...

Duckdude
April 4, 2011, 02:13 PM
Hello gunners, I'm new to this site so please bear with me. I just aquired a mint Remington 788 in .243, carbine - short tube, think it's 1 in 9 twist. Took two antelope Oct. last year in wyoming, both inside of 150 yds. My concern or interest would be any suggestions for a load that will optimize that rig for deer / antelope / coyote for the max. range (inside 300) for me. It wears an old 2x7 Redfield, I'm using a 90 grain bullet...good groups 100, 200 yds., big drop at 300. Heavy rig, even with the short barrel, love shooting it - recoil like a .22.. but would like to go to a heavier slug, if possible...or reasonable. Have not chroned that load, custom through Conley Precision Cartridge...I know I'm probably losing 200 fps. + from a 22 / 24 inch barrel. Any thoughts appreciated. Powder / bullet 100 gr., .....Thanks!

JerryM
April 4, 2011, 05:25 PM
I much prefer 22" barrels in standard cartridges for deer and above game.

As far as performance my handloads in my .243 WCF 100 gr and .270 WCF 130
M70 FWT pre 64 rifles with 22" barrels chrono 3150 and 3100 respectively.
I often wonder if those who are so set against 22" barrels have ever owned or chronogrphed one.

I could not say that the .243 and .270 are the best for short barrels. I see no reason why other cartridges like the .308 and 30-06 are not as efficient. Maybe a little more efficient. However, I don't really care about efficiency, but what performance I am getting out of the individual rifle.

Regards,
Jerry

ms6852
April 4, 2011, 06:05 PM
I have to agree with some of the people that would choose the 7mm-08. This round is a sleeper which has a flatter trajectory than the 308 and the 30-06. The recoil is less than the 308 and at 300 yds delievers more energy ballistically using a 140 grain bullet vs the 150 grain bullet of the 308 and about the same energy of the 30-06 with the 150 grain remington core-lokt. This caliber would make a great scout rifle.

Of course there is always the venerable 30-30 winchester or the 35 remington. But since you wanted a varmint rifle as well the 7mm-08 makes it a wonderful caliber for varmint as well as big game.

Duckdude
April 16, 2011, 01:56 PM
Thanks Jerry...no, I agree...I just sort of inherited the carbine. Have a lot of rifles 22" to 26" bbls., I'm just sort of stuck with the 18" (ouch) tube. Fun to shoot though. Makes me wonder why Rem. would produce that rig...given the velocity drop.

JDMorris
April 16, 2011, 02:19 PM
.338 Federal = .308 case necked up to .338, perfect for a brush gun.

Art Eatman
April 16, 2011, 02:39 PM
Duckdude, if you still have questions after reading through this year-old thread, feel free to start a new thread.

If you enjoyed reading about "243 or 270 for short barrels?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!