rifle barrel length

Status
Not open for further replies.
H

hartmen

Member
Joined
Jun 5, 2010
Messages
108
driving down the highway today me and the wife got to talking about guns. the question poped up that i had no answer to and i immediatly thought of this forum......

i know barrel length of a shotgun can be no shorter than 18"

how about rifles? what are the tolerance for them? even though it makes no sense to cut a rifle barrel down.
 
i say that because the basic purpose of a rifle is accuracy. cutting the barrel down will decrease that. not saying the longer the barrel is the more zero on your shot will be. sometimes longer the barrel the more drag you will receive on the bullet
 
Not necessarily. Consider a handy 16" barreled rifle while hunting and maneuvering through thick brush. It is fully capable of the accuracy needed for its purpose while being usable in that environment. You may be sacrificing some velocity for the given caliber over a longer barrel, but any rifle is a compromise for its use.
 
shorter barrels give up velocity, recoils more and are louder but have more stiffness which can actually make them more accurate.
 
Velocity - Agreed. The shorter barrel does give up some velocity (have seen debates ranging from 25 fps/inch to 90 fps/inch...the truth is probably somewhere in the middle).

Recoil - Not so sure. The length of the barrel should not have a substantial impact on recoil unless you're accounting for the loss of weight that results when you lop off several inches of barrel (i.e. a lighter rifle has more felt recoil than a heavy rifle). Likewise, there may be some very small difference in actual recoil due to the gas bleeding off as the bullet exits the shorter barrel but my guess would be that that would actually reduce felt recoil (though not enough to be noticeable and probably not enough to overcome the perceived increase due to the muzzle blast).

Muzzle blast - Agreed. Shorter barrels are "louder." That's measurable and factual.

Accuracy - Interesting topic with good arguments on both sides. I tend to be of the mindset that as long as the barrel is long enough and has an adequate twist to stabilize the bullet...there probably isn't an advantage (and may be some disadvantages such as stiffness) of going longer. As long as the barrel is well tuned (i.e. the harmonics permit repeatable departure of the bullet from the barrel) I don't think there's a huge disadvantage to long barrels either.

Bottom line...seems to me that the advantage of a short barrel is almost entirely that it is "handy." The disadvantage (for me) is purely velocity loss. In the end, however, I'm glad we get to pick our favorite and shoot whatever we like (within reason;-)

Happy New Year!!
 
say that because the basic purpose of a rifle is accuracy. cutting the barrel down will decrease that
Click to expand...

Incorrect, accuracy is not affected by the length of tube through which the bullet exited.
 
If you want to learn how a barrel reacts during the shot, go spend some time at Varmint Al's website. Shows harmonics, etc. Extremely complex.

FWIW....shorter, stiffer barrels typically tend to be more accurate. Look at heavy bench rest guns.
 
Shorter barrels tend to be more accurate, not less. At least when using optics. Longer helps with people shoot irons more accurately since there is a longer sight radius.

Shorter is handier and easier to use quickly in many situations. You do give up a little velocity with some rounds, but much less than most folks believe.
 
IIRC, the URL is http://www.secretsofthehoustonwarehouse or you can Google for it. Lengthy but very interesting. The guys finally pretty much agreed that the best barrel length for minimum groups size (and they were going for groups tiighter than a tenth of a minute of angle) was 21.75 inches.

As far as velocity loss per inch of cutback on a barrel, it will vary with the type of cartridge. As near as I can tell from a helluva bunch of years of reading many tests, you can figure around 100 ft/sec for such as the .300 Win Mag or longer case. Around 75 ft/sec/inch for cases dimensioned like the '06 family. Maybe 40 to 50 for such as the .308, and not much different for the .223.

So far as I can guess, it's something to do with the ratio of length to diameter, maybe--at least for the generally-larger cases than such as the .223. Damfino...
 
Velocity loss is commensurate with unburned powder and excess gas pressure being released - if it's louder, it's also not efficient (for powder consumption). New .223 loads coming along burn slower powders and will take advantage of barrel length. So it really boils down to the load you want to push?
 
Velocity loss/gain also depends on the barrel itself as well as the velocity of the caliber. It can vary from 5 fps per inch on up.
 
barrel length only affects the velocity of the bullet. Mechanical accuracy of a rifle is based, on how well the parts of the rifle mate, how little outside interference affects the rifles ability and the level of quality of ammunition shot in the rifle.

If you shoot a .308win match grade ammunition, you will find a level of accuracy that will keep tight groups with 100 to 200fps variance, if all rounds shoot within the same fps.

So with a 24" bbl my match load shoots 1/2 MOA, with a 16" barrel, its still shoots 1/2 MOA just a point of impact shift do to how slow the bullet is, because the barrel is shorter, there for the vol is less, but the accuracy is still the same.

I loaded some hand loads for my 22" bolt action, they shot 1/2 MOA, I took the smae handloads and shot them in my DPMS 16" LR-308 and I had the same group size, but 100fps slower.

John
 
Status
Not open for further replies.
Back
Top