243 or 270 for short barrels?

[dakotasin]

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]

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]

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]

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]

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]

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]

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]

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]

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.

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]

I think the 6.8SPC (270 Bantam) is designed around use in a short barrel.

 

[pmeisel]

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]

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]

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?

 

[Rokman]

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]

I would love to have a 6.8SPC carbine bolt action.

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

 

[Rokman]

Abel, I really like that Ruger, but the twist is too fast. It would be a handy little sucker.

 

[Abel]

What weight bullets do you want Rokman?

 

[Rokman]

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]

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]

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]

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]

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]

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]

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]

"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?

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?