Barrel length 20" compared to 24" & 26" in 30.06?


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mickeydim468
March 6, 2009, 03:01 PM
I have no idea why the length of the barrel makes too much difference other than that it has a longer contact with the bullet to make it spin better and would make it fly straighter. I also know it has something to do with muzzle velocity because it allows the powder more time to ignite so more of it's energy will be used for bullet propulsion.

This is my laymans terms explaination. Can anyone explain it to me in technical terms and tell me the differences between the three lengths? Please give examples and numbers if you can. I am an engineer so numbers make sense to me. :D

Also, which barrel length would be the better choice for long range hunting for deer and Elk? I do not want to discuss caliber just barrel length.

Thanks!

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USSR
March 6, 2009, 03:21 PM
mickeydim468,

One of my .30-06 rifles is a tactical rifle with a 26" Krieger barrel. For this particular rifle, I load 190 grain Sierra MatchKings with pretty much a case full of RL22 powder, and easily reach 2900fps for 1,000 yard shooting. From a 100 yard zero, I only need 30MOA to reach 1k. If I tried this load with a 20" barrelled .30-06:

a. I would not reach anywhere's near that velocity.
b. My trajectory would be more pronounced due to the lower velocity.
c. The wind drift of the bullet would be greater due to the lower velocity.
d. There would be a HUGE muzzle blast due to the remaining high pressure
at the end of the short barrel.

So, essentially, if you want to take advantage of the .30-06's large case capacity by using heavy bullets with slow burning powders for long range shooting, don't use a short barrel. Hope that helps.

Don

NCsmitty
March 6, 2009, 03:25 PM
I see that you skipped over the 22" length. I think 22" is a very handy size for all conditions. It will give you 40-50 fps over the 20", depending on the load. The longer barrels will give you more fps but will become more unwieldy if you carry afield, that is unless you're a "catered" hunter and you're driven to your stand and picked up with your kill. Then I guess any length will do.

NCsmitty

kragluver
March 6, 2009, 03:25 PM
The "optimum" barrel length for the '06 with middle weight bullets is 24". As you originally stated, the longer barrel length allows the powder pressure to act on the base of the bullet longer. Heavier bullets "like" longer barrels. If you go with a barrel shorter than 24" in the '06, muzzle velocity starts to drop, muzzle blast and flash are much greater too as more powder is burned outside the muzzle. However, a 22" or 20" barrel sure makes a handy rifle! If you want a short barrel rifle, look to the moderate case capacity cartridges like .30-40, .30-30, .303 Brit, etc.

interlock
March 6, 2009, 03:49 PM
i have a 24 inch barrelled .30-06 and i also have a 18 inch barrelled model 7. in an actual practical hunting situation the extra 6 inches of barrel are not a handicap in any way. i like the lightness of the model 7 but the .30-06 is where i reach when the shots are over 200 yards.

jpwilly
March 6, 2009, 04:08 PM
The M1 Garand is 24" Most hunting rifles are 22". Shorter barrels are often more accurate in light weights because they are stiffer (less whip) but as others have said loose velocity and make more noise. Longer barrels have little to do with accuracy and much more to do with velocity. Allowing slow powders to burn completly you must have a longer barrel to take advantage.

I've often wondered myself why barrels had to be rifled to the end. Why not just put rifling into the first or last half of the bbl and then make the rest a smooth bore to gain velocity. I'm courious if this would cause the bullet to stop spinning and thus destabalize the bullet or if it would actually work?

mickeydim468
March 6, 2009, 04:32 PM
Here is the thing...

I have a 20" 30.06 for close up and in the brush work. I am having made a 30.06 for longer range game up to and including Elk. In the area I will be using this rifle, yes it would be a taxi type of hunt over long range with little or no brush, just open plains type of work.

So I am trying to decide on the length of the barrel. I would like to see ballistics of similar loads used on different length barrels to see if I am barking up the wrong tree or not. Does anyone have any of this type of data?

NCsmitty
March 6, 2009, 05:09 PM
Here's a link to some info on barrel lengths.

http://www.loadammo.com/Topics/October05.htm

NCsmitty

mickeydim468
March 6, 2009, 05:26 PM
Thanks for the link Smitty,

So, if I read that table correctly then I would gain approximately 133fps over my current 20" barrel at the load he used as an example, if I use a 26" barrel on my new rifle. or an increase of about 39fps more than a 24" barrel. How would that translate into accuracy and energy?

NCsmitty
March 6, 2009, 06:09 PM
Here's the www.realguns.com kinetic energy calculator. Just plug in the info.

http://www.realguns.com/calculators/kineticenergy.html

Accuracy is up to you and the barrel you select.

NCsmitty

SaxonPig
March 6, 2009, 07:07 PM
The difference between a 20" 30-06 and one in 24" is about 100-150 FPS depending on bullet weight.

Not sure how 24" is "optimal." Define "optimal." It's not maximum velocity because the velocity will continue to increase in longer barrels up to 30" or more. Even the lowly 22 Long Rifle goes faster in a 29" barrel than in a 24" tube and this surprised me.

I think the primary function of a short barrel is handiness. The velocity loss generally isn't enough to cause great concern and I think you are mistaken in thinking that a 24" 30-06 will do anything significantly better than will a gun in the same caliber with a 20" barrel. Not enough to warrant packing around two rifles, IMO.

warnerwh
March 6, 2009, 08:24 PM
If you're going through a lot of thick brush then the 20" would be my pick otherwise a 22-24 is fine. What matters the more is how good of a shot you are at long range. The difference in velocity and trajectory isn't that great imo. If you haven't practiced at 300 yards you need to so you don't just injure the animals allowing them to run off and die a slow death.

I'm just suggesting the practice because if you're new then I'm betting you haven't tried shooting at that range. See how good you are using the bench at 300 yards. Then test your skill leaning against something if possible, prone and kneeling. There's probably not going to be a bench where you're hunting. You'll have fun doing this kind of practice too.

jmr40
March 6, 2009, 08:55 PM
One of the great things about the 30-06 is that it is versatile. With the right loads and a long barrel it is as good a long range rifle as ever. With a shorter 20" barrel they still get enough velocity to work well at most hunting ranges.

The 22"-24" are a good compromise and work well for most people. I personally like a 22" better. If I am going 24" or more I'll take the 7 mag. Others like the looks and balance of the 24" better and I will not argue that they are wrong.

Redneck with a 40
March 6, 2009, 09:43 PM
The .308 works well with 20" barrels, the '06 needs a longer barrel, more powder in the case. I'd say 22" would be minimum in the '06.

mickeydim468
March 6, 2009, 10:40 PM
Well, I was only wondering, because I already have the 20: 30.06 and am happy with it for what I am using it for. I just wanted to know which would be better a 24" or 26" for a longer range shooter, and to gather some data as to how much better it will be in comparison to my 20".

I was hoping that someone would have some hard core specs and real life experience between the three lengths, and get some confirmation, that my thought process is on the right track here with my custom rifle build.

In theory, the 26 would be better, and 2 extra inches will not make that much difference in the wielding of the rifle I am sure. I couldn't imagine that it could weigh more than a few ounces for a 2 inch piece of the muzzle. My other thought is why not!

I thought to myself; "Why not do something a little bit different and unique with my project." and that is all I am trying to accomplish. The rifle so far will be a Mauser 98 action, with a Kepplinger single set trigger, a 26" stainless barrel in 30.06, a 4-16x40 scope, and a hand made stock made out of the builders choice of hardwood. This will be my goto gun for longer game shots for deer and elk. anything over 200yards.

I will be doing quite a bit of practice with this before I ever go hunting with it, so I won't be too worried about my ability. I just want to make sure the rifle is more accurate than I am. :cool:

jpwilly
March 6, 2009, 10:55 PM
I have lots of experience with 22" and 24" bbls and none with 20" or 26". Only the chronograph can tell the difference.

rangerruck
March 6, 2009, 11:24 PM
for most center fire carts, bbl length stops mattering at about 20 or 22 inches, Even for benchrest , long distance shooters, they pretty much stop at 26 inches. A 30.06 round can fill a tube with gas , in a bbl that is 38 or 40 inches long. But that would be impractical. A good 22 or 24 inch bbl, is plenty for a 30 .06 , and plenty accurate. Twist is twist, that is, once it has twisted a bullet 1 full revolution, bbl lenght, speed, all that crap means little, especially if it is a well made bbl. It gets no more accurate with a longer bbl, just becuase you are adding twists, it doesn't twist any faster, it is spinning around an axis, and that is that. Now then, if you have both a long bbl, that is really fat, thick , and stiff, then that is typically more accurate, than a long bbl, that is not thick, even if this bbl is longer, than the fat thick bbl.

rangerruck
March 6, 2009, 11:27 PM
one more thing; it takes a really fast, bangin hot cartridge, to make up 50 fps per inch of bbl, esecially again, after the bbl is allready 20 inches or longer.
I would say that on avg, the 30.06 is only gaining at most 20-30fps per inch, depending on the cart weight.
Look at our military snipers, they are taking 1000yds shots, with 308's and such, with 22 inch bbls.

usmc1371
March 7, 2009, 12:06 PM
I think most of the factory ammo for the 06 does about all its going to do in a 24" tube. I have been shooting a 22'' ruger for 18 years and its never let me down. A friend of mine picked up a 24'' remy a few years ago and I would take the extra 2'' if I was buying a new one.

Art Eatman
March 7, 2009, 01:59 PM
Back before most of you guys were born, it was common for the gun and ammo manufacturers to give rubber pads to gun shops to protect the display cases from scratching. Maybe 15" x 24", mas o menos. The top often had ballistics data for their cartridges.

Generally, all testing of almost all rifle cartridges was from 26" barrels. It was common for the folks at such places as the American Rifleman's "Dope Bag" to meddle around to figure out answers to all manner of questions. A common question was the effect of shortening barrels from the "standard" 26".

The most common number for the .30-'06 and similar cartridges was 75 ft/sec/inch. For magnums, around 100 ft/sec/inch. Then, with the change in relative dimensions of such as the .308/.243, the common answer was around 40 ft/sec/inch.

Caveat: "There ain't no always."

While I've never had a chronograph, I could tell from results at 400 and 500 yards what my '06 was doing with its 26" barrel. You can work backwards from a known distance and the trajectory with a given bullet to look up the muzzle velocity required to produce the result. "It's in the book." The Sierra reloading handbook, anyway.

Based on comparative results with my and other folks' shooting at my range with rifles of shorter barrel length, I pretty much go along with the Dope Bag findings.

lefteyedom
August 27, 2009, 02:26 AM
Fit and balance of a hunting rifle is more important than an extra 100 to 200 fps. Once your cartridge reaches 2500 fps with 165grn or heavier 30 caliber bullet you can kill anything you want in North America.

If you like a 28" barrel then by all mean carry it.
I like my bolt action, 20" barrel 30.06 with a 2X7 scope. Short but not too short, fast to the shoulder and fit my 5'8" frame well.

natman
August 27, 2009, 10:33 AM
I have no idea why the length of the barrel makes too much difference other than that it has a longer contact with the bullet to make it spin better and would make it fly straighter.

Sorry, not true. A longer barrel is slightly more flexible than a short one. A longer barrel does provide a longer sight radius if you are using iron sights.

I also know it has something to do with muzzle velocity because it allows the powder more time to ignite so more of it's energy will be used for bullet propulsion.

The burning gasses get to push on the base of the bullet for a longer time with a longer barrel, hence more velocity.

In a 30-06 a 22 or 24" barrel is the best compromise. Longer than that the rifle affects the balance and handling of the rifle. Shorter than that cuts down on the ballistics and increases the blast.

SpeedAKL
August 27, 2009, 10:58 AM
A 20-inch barrel works fine on a short-action cartridge such as a .308 - many high-end tactical rifles are built with barrels of this length. However, a long-action cartridge like a .30-06 typically maximizes performance using slower-burning powders versus the faster-burning powders in a short-action catridge like a .308; this requires a longer barrel to get to the higher velocities that the .30-06, .300 Win Mag, etc offer over the .308. This may not make a huge difference in a hunting rifle shooting inside 300 yards or so, but for long-range precision applications it becomes important as faster cartridges *generally* shoot flatter.

Uncle Mike
August 27, 2009, 12:39 PM
A 20-inch barrel works fine on a short-action cartridge such as a .308 - many high-end tactical rifles are built with barrels of this length. However, a long-action cartridge like a .30-06 typically maximizes performance using slower-burning powders versus the faster-burning powders in a short-action catridge like a .308; this requires a longer barrel to get to the higher velocities that the .30-06, .300 Win Mag, etc offer over the .308. This may not make a huge difference in a hunting rifle shooting inside 300 yards or so, but for long-range precision applications it becomes important as faster cartridges *generally* shoot flatter.

True...Ever notice that pretty fireball just outside of the muzzle... that is gas burning off in the atmosphere, gas that, if you had a longer barrel would be utilized to push the bullet, increasing the bullets velocity.

The bullet is stabilized, as far as spin is concerned in the first tiny bit of barrel, the rest of the barrel is simply used as a chamber in which powder turning into gas through burning, creating pressure inside this chamber, because both ends of the chamber is plugged off, is allowed to push the bullet.

Hypothetically speaking...
There is a curve,(mathematical) in which the push of the gas finally subsides... if this point is reached when the bullet is still in the barrel, then you have strained all your going to get out of that powder charge, if not, and the bullet exits the barrel before this peak is reached, then you get the fireball and at that point you have no more push on the bullet... put in my worst laymen terminology...lol

I made up a rifle not too long ago, the customer wanted some 'numbers' as you do...

It was a 30-06, 24" using the 165gr. Hornady SST bullet.

The difference between a 22" and 24" barrel using the above factory load...

Distance in yards/Velocity fps/Energy lb.ft./Drop inches (24" decrease to 22" barrel)
200y zero-
Muzzel...50fps/109lb.ft./0"
50y.......48fps/103lb.ft./.1"
100.......48fps/96lb.ft./0"
200y.....46fps/85lb.ft./0"
300y.....43fps/76lb.ft./.3"
400y.....41fps/66lb.ft./.7"
500y....40fps/58lb.ft./1.5"

So you see going from a 24" barrel down to a 22" barrel his losses were mute.
As far as drop, at the ranges he was planning on shootin, he did not hardly have to correct till the 400y(3/4") and 500y(1 1/2") ranges.

ArmedBear
August 27, 2009, 12:50 PM
I'd hope you wouldn't be shooting anything at 500 yards with a .30-06, where 1 1/2" mattered. Even an honest-to-god 1/2 MOA rifle would shoot 2 1/2" at 500 yards from a machine rest.:)

CaptainCrossman
May 10, 2012, 06:09 PM
old thread, good topic- 20" is too short for the 30-06 cartridge for hunting with full on loads and 150-220 grain bullets. It's not in regard to accuracy or power, but in regard to muzzle blast and noise. It kills your ears. Most replies will state "I took this or that animal with it no problem" on a short barrel. Well no kidding, so will a 44 magnum DA handgun with a 6" barrel for that matter. The real question is, do you want to put up with the muzzle blast in your ear from the shorter barrel from an 06, and a gun that kicks like a mule. It does a number on your left ear. (or right ear if your a left handed shooter). The best I can describe it is, blowing off a 1/4 stick or M-80 in midair only 20 inches from your ear with no protection- get the picture ? That would hurt, and so does the 06. The little extra barrel length goes a long way to move the pressure blast away from your ear. The 06 has a pretty large powder capacity for a non-magnum cartridge, it's not a low intensity round like a 30-30 or 32 Win Spl. or 35 Remington. You really don't want a 308 or 30-06 or 8x57 with only a 20" barrel, unless you have hearing protection. The recoil and blast will be excessive because these guns usually are pretty lightweight as well. 22" is optimum on the short side for a barrel. I've found 24" to be ok as well. 25" and longer is too long for woods hunting.

jmr40
May 10, 2012, 08:58 PM
There is a reason most manufacturers have settled on either 22 or 24" as standard for the 30-06. Those are the best balance between velocity and handling. You pick one or the other to get a rifle that looks and balances the way you want it to, not because of velocity. There isn't enough to matter beyond 22", at least not on a hunting rifle. Going to 26-28" might give you 50-100 fps more speed over a 22" barrel. On a 1,000 yard target range that might matter, not on a hunting rifle.

You will often see folks quote figures of 10,20,or 50 fps for each inch longer or shorter. On average this is about right depending on the chambering, but it is not linear. Going longer than about 22" in a 30-06 gives you very small gains per inch, and the gains continue to be smaller as you go longer. Going shorter the losses get larger and larger the shorter you go. If you were to chronograph loads from a 26" barrel then gradually shorten it 1" at a time and chronograph it at each length until you get to 16" you'd see around 250-350 fps total loss for an average of 25-35 fps/ inch. But the velocity loss between 26" down to 22 would be very small and you wouldn't start seeing big chunks until after you get under 20"

Another mistake people make is comparing the velocities they get from 2 different guns. It is meaningless. Only the data compiled from shortening the same barrel and when firing the same loads under the exact conditions is worth looking at. Between family and friends I load for 7 different 30-06 rifles. 4 with 22" barrels, 2 with 20" barrels and 1 with a 24" barrel. My best loads of 150 gr bullets shoot at the following speeds from the 4 guns with 22" barrels

3025 fps
3015 fps
2990 fps
2965 fps

The 24" gun shoots the same ammo at

3025 fps

The 20" guns shoot the same ammo at

2900 fps
2910 fps

While that is a big loss compared to the fastest 22"or 24" barrel it is only 55 fps slower than the slower 22" gun. And still right at published velocities with factroy ammo from 24" barrels. They shoot factory ammo within 60 fps of velocitities published for 24" barrels.

Lots of folks say a 308 is a better choice for a 20" barrel. Maybe, but my 20" 30-06's are still 100 fps faster than factory 308 ballistics from a 24" barrel.

I guess muzzle blast is subjective. The 20" guns are a little louder, but I struggle to notice the difference. It is still quieter than a 24" magnum rifle. Weight is not a factor. Losing 2" of barrel is around 2 oz. The 2" can make a difference in really thick brush. I'm pretty happy with 22". The 24's just don't add enough speed to justify the awkward balance and looks in my eye. If others prefer that look and balance I have no argument. I rarely hunt with my 20" gun, because I just like the 22" ones better. But it's not a bad length if you want to use it.

adelbridge
May 10, 2012, 09:46 PM
A .30-06 out of a 20" barrel is going to perform about the same as a .308. Send a 7mm rem mag down a 22" barrel and it is going to give you .30-06 performance.

B!ngo
May 10, 2012, 10:01 PM
Would it be too much of a detour to restate the questions here for .308? I'm looking at a bolt rifle that has the option of a 20" or 24" barrel. I'll use it mostly for mid-range paper but also want to reserve the right to hunt with it every now and then, and just don't want to carry a clumsy rifle if the marginal value is small.
From the off-hand comments re .308 in this thread, it seems like 20" is a fair length for .308 but just would like to hear more. And perhaps asked differently, when would someone choose a .308 in 24"? I'm sure they don't make that barrel for nothing.
Oh, and yes I suppose I don't 'need' a .308, but always wanted one.
B
P.S. (let me know if you'd prefer me to post a new thread)

trapper500
May 11, 2012, 03:21 PM
The longer a barrel is the better i like them. My 300 WBY Vanguard iam paying on has a 24" barrel & i wish it was 26" or 28".My wife's little 243win Mossberg TREK has a 20" barrel she likes it so its good for her.It does shoot good but the shorter barrel will effect the shot at long ranges my Handi Rifle 500 S&W mag has a 22" barrel & i love that little monster its get greater velocities over the shorter pistold barrels.JMHO:D

451 Detonics
May 11, 2012, 09:09 PM
I will go out on a limb here and say 21 3/4 inches is the perfect barrel length, not much velocity is lost and it is the best length for accuracy according to Virgil King. This is man who is used to shooting rifles that arc so I assume he know what he is talking about.

Art Eatman
May 11, 2012, 11:10 PM
The 21.75" number came from this commentary:

http://www.angelfire.com/ma3/max357/houston.html

"Secrets of the Houston Warehouse".

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