Barrel length versus accuracy

[craig110]

This is an interesting read: http://www.bellmtcs.com/store/index.php?cid=580 I used to think that longer barrels equaled better accuracy due to increased velocity, but for a while now I've been reading suggestions to the opposite. In the test the article is describing, they took 28" barrels and cut them down to 23" and got significantly better MOAs out of the guns.

Perhaps with the exception of long-range shooting where every FPS can make a difference, shorter barrels are better.

[Rollis]

I, have not read the artical yet but it would be my guess that the main problrm with the longer barrle is more vibraton. That is one of the reason's for the heaver barrle's to dampen the vibration. If you could get an efitiont enough burn. all you would need is a one inch barrle +/-.

[Rollis]

Just read the artical, and it was not anything earth shatering new. The most interesting part I, found was that there was loose spot's in the rifling. One would hope that at this time in our develipmont the maching could be good enough to eliminate this.

[Blackdog]

One factor in accuracy is barrel whip (harmonics), so it stands to reason that a shorter, stiffer barrel would be more accurate. That's why barrel weights/dampeners can help. The much-maligned Mini-14 benefits greatly from this treatment.

[CZ93X62]

Agreed. Barrel harmonics, and like earthquakes those harmonics have "P-waves" (primary) and "S-waves" (secondary). In a barrel, the P-waves resemble a flagPOLE in the wind, while the S-waves are SINUOUS like a SIDEWINDER/SNAKE. These waves are simultaneous in occurrence, and as noted above can be attentuated by thickening a barrel, and exaggerated by lengthening a barrel.

My decent loads with the Mini-14 and other whippy barrel contours have much to do with finding a load that produces unvarying harmonics in concert with the rifle's bedding and barrel contact characteristics, and not allowing the barrel to get very hot and start heat-induced weirdnesses. I am amused by those who condemn Mini-14 accuracy, while singing the praises of levergun utility and practicality. Such bloviations tell me that the announcer is likely not deeply acquainted with either system, and even less familiar with making so-called "marginal" systems operate optimally.

[Glooooock]

One factor in accuracy is barrel whip (harmonics), so it stands to reason that a shorter, stiffer barrel would be more accurate. That's why barrel weights/dampeners can help. The much-maligned Mini-14 benefits greatly from this treatment.

A. Swenson , use to make 20 " barrel rifles . He told me get the bullet spinning and out as quickly as possible worked best , 1988 .

Even those short barreled M4's will hit a 10" ring every time 3 - 4 hundred yards .

I figured the last few inches on longer barrels the bullets seal in gone . The muzzle's bore ends up eroded & widened . The poor mans fix was to cut an inch or two off an old barrel . Thread the barrel another 1/2 thread deeper in the receiver / action , run the reamer in for a clean cut throat / chamber .

[MONTEGOD7SS]

A factory barrel cut back and recrowned is not a good test for a shorter barrel. A good aftermarket barrel with a good crown, then cut back and recrowned, maybe. I personally like long barrels, the longer the better. If a "little" extra velocity didn't matter, then we would all be shooting .30-30s instead of .30-06s.

My hunting rifle is an -06 for the very reason that I can push a big bullet faster, so why would I go with a shorter barrel and lose that advantage? If I lived somewhere that didn't have regular 500yrd shots maybe, but then I'd probably be using the .30-30 I mentioned earlier.

[Glooooock]

A factory barrel cut back and recrowned is not a good test for a shorter barrel. A good aftermarket barrel with a good crown, then cut back and recrowned, maybe. I personally like long barrels, the longer the better. If a "little" extra velocity didn't matter, then we would all be shooting .30-30s instead of .30-06s.

My hunting rifle is an -06 for the very reason that I can push a big bullet faster, so why would I go with a shorter barrel and lose that advantage? If I lived somewhere that didn't have regular 500yrd shots maybe, but then I'd probably be using the .30-30 I mentioned earlier.

I think the question is accuracy , the 20" barrel may shoot better than a longer rig 300 -400 yds . At long ranges the faster .30 cal loads aren't much faster than a .308 , maybe a bit flatter shooting 500 + yd ,using the same bullet . All but the slowest powders are burned up in 20" -24 " of tube .

[MONTEGOD7SS]

But every little bit helps. Like I said, we would all be shooting .30-30s if velocity meant nothing. I will take a fast .30 over a slower .30 any day of the week, and my 24" barrel out of the box Remington has given me .250" groups. If I re-barrel it it will probably be a 28". I will find a load that shoots good (reloading advantage ya know) either way and will gladly take the extra speed from a long barrel.

[Blackdog]

As handloaders, we can tune our ammo to the gun. That mitigates some of the problems of barrel oscillation. I also believe that modern barrel making technology is giving us consistency only available from the custom shops not that long ago. I think that the short vs long barrel, accuracy vs velocity discussion has alot to do with what is practical to your application. If your goal is to shoot bug holes at 100 yds, maybe a short, rigid barrel will serve you best. If you wanna reach out and touch stuff, a longer tube give the added velocity needed.

It's great to have such choices, eh?

[Rollis]

Has there ever been a study that showed how much the diamiter for a barrle of a given caliber has to increse to match the length of a barrle?

[Glooooock]

I think its specific to the type of shooting , you don't want to carry a 28" 1.250 barrel all day in the woods or mountains . A short fat barrel will have reduced harmonics and shoot any ammo better . So in a perfect world with the Stars aligned when your .30 Cal is up in 3000 - 3300 fps range and you go from 20 " to 28" the best you can do is 200 - 240 FPS at the muzzle . At the 500 - 600 yd end I doubt it would be 100 fps fasters ,,,,, But flatter & fasters is always a plus . Ball park gains are 20 - 30 fps per inch at the muzzle , so 24" to 28" would be a more realistic range , with slower lower BC bullets being worse . See link ,,,,its the bottom section of the 3-4 pages .

Barrels / Velocity (http://www.chuckhawks.com/rifle_barrel.htm)

[creophus]

Good article. The guy saw a dramatic increase in accuracy.