barrel change questions

[jundeleon]

If I swap my 16 inch barrel on an A1 upper into with a shorter 11.5 inch barrel, what other parts do I have to change (aside from the handguard?

Will this set up cycle reliably?

[fastvfr]

Sometimes it will run okay; other times you'll need to tweak the gas system, either by installing a pigtail or by overboring the gas takeoff hole in the barrel and adding a valve to the tube for regulating the flow.

Either way, this gives a sharper, shorter-duration impulse, and that can lead to premature extraction attempts (and case heads ripped off) as well as excessive bolt speed if it makes the lockup disengage much sooner than normal.

And unless you have registered it as a NFA, you'll need at least a 4.5" barrel extension permanently mounted to give you the minimum legal length.

Other than that, the location pin often needs changed, and the barrel nut is often not re-used especially if it gets too deformed in the removal process. Aside from that, everything else should swap over if both the original and the replacement barrels are Mil-Spec.

One thing, though. Why do you want to do this?! You'll lose over 200FPS on an extremely velocity-dependent cartridge, as well as adding noise. And this usually somewhat reduces the accuracy potential of the weapon.

But it is your baby! Have fun!

FastVFR