Shortest barrel length with rifle length gas system?

[jurassic]

I have a twenty one inch barrel that shoots well, it has a rifle length gas system and functions just fine. I want to build another rifle, but short barrels are impossible to find. I don't like the gun because of the weight and length (it's a hunting rifle,) can I cut it down to 16" and still have it function properly? It does have an adjustable gas block.

[Drifter]

I wouldn't go shorter than 18" on rifle-length gas.

Adjustable gas blocks are primarily for overgassed systems. The concern with going shorter than 18" is not enough gas to cycle the action reliably. A malfunctioning AR doesn't usually perform to its accuracy potential. You would likely have to enlarge the gas port if cut to 16", but that's an inexact science with the muzzle and gas port so close together. And I don't recommend relocating the gas port either.

Go 18" and be happy.

[jurassic]

Thanks, I should probably just leave it alone and get on the wait and notification lists for barrels again.

I wouldn't go shorter than 18" on rifle-length gas.

Adjustable gas blocks are primarily for overgassed systems. The concern with going shorter than 18" is not enough gas to cycle the action reliably. A malfunctioning AR doesn't usually perform to its accuracy potential. You would likely have to enlarge the gas port if cut to 16", but that's an inexact science with the muzzle and gas port so close together. And I don't recommend relocating the gas port either.

Go 18" and be happy.

[Drifter]

Thanks, I should probably just leave it alone and get on the wait and notification lists for barrels again.

I was in no way trying to discourage you from cutting your barrel. Actually, I encourage it because of this...

...I don't like the gun because of the weight and length (it's a hunting rifle,)...

A good barrel will not go bad if properly cut and crowned. And since you don't like the rifle as is, no reason not to alter it to your satisfaction. Adco could make quick work of the alteration, and it wouldn't be too costly.

FWIW, an 18" Grendel with rifle-length gas is my favorite hunting setup. More than once I've purchased 20" or longer Grendel barrels with the intent of cutting then back. The only exception has been a 20" with target crown, which is approximately the same length as an 18" with a muzzle device. (Hint: Cut your barrel to 18" with a target crown to effectively get the length of a 16" with muzzle device.)