Is there any reason to have an AR-10 with 24" barrel?

[wild_wild_wes]

I just bought an Armalite 24" T barrel for my AR-10 build. I see many guys have at the most a 20" tube. Should I have my gunsmith cut my barrel down when the rifle gets built, or leave it a full length? I plan on shooting out to 1,000.

[tolson68]

For the most part it comes down to FPS and weight. If you want to max out your FPS the 24" will deliver slightly higher muzzle velocity than the 20", but you will pay the price in weight. How far do you intend to shoot?

[Puffy93]

If your planning on shooting to 1,000 yards a 24" bbl would probably work better than a 20" IMHO

[DRich]

While I shoot 20" .308 guns at 1k on occasion, I get much better results from my 24" - 26" rifles. The extra velocity really helps once you get out past 800yds. You want the bullet to stay supersonic as long as possible. Once it goes trans-sonic, the groups open up.

[Littlelebowski]

I had mine cut to 20.75"

[Ricardus]

The M14 has a 22 in barrel. The USAMU found that a 1X10 twist shooting 175 grain bullets enabled them to have better stability. The 175 gr. bullet remained supersonic. Some bullets stay stable even when transitioning to below supersonic speed - the old 173 gr. Lake City Match ammo I believe. Some bullets destabilized below supersonic when approaching the 1000 yard targets. Remember the M14 is a semi-automatic rifle.

So if you intend to shoot 1000 yards, the correct combination of twist rate, bullet weight, barrel length, caliber and whether or not it is a semi-auto or a bolt-action rifle will determine the stable and consistent arrival of the bullet to 1000 yards and beyond.