Shorten barrel on a gas operated semi auto?

[jcn59]

Couple years ago I bought an older .270 BAR, made in Belgium, assembled in Portugal.  Some genius hacksawed off the barrel a tad over 20" & rounded off the muzzle on a bench grinder or worse. 

I got a deal on it & the shop was glad to see it go.

I crowned the barrel on my lathe &  found it functions perfectly even with RN 150s.  Shoots from 3/4"  & up to 2" at 100 yds. or so depending on the phase of the moon.  Usually about 1.5".  I shoot a few factory loads but 90% reloads including RN 170.  It digests them all w/o a hiccup.  No gas port work at all.  Recoil is little to less.

[BBF]

I got a Rem 742 at the 'smith to get the barrel cut back to 18 1/2 inch, he assured me it would cycle just fine.

[Totenkopf]

 I had a fellow bring me a 7400 rem that he had stuck the barrel in the mud then shot at a deer. I chopped it off at 18", recrowned and milled out front sight base. It functioned well.

[targshooter]

Whether carbine or rifle, the gas port and recoil mechanism are the same in the Remington 7400 and the BAR. So for these firearms this would infer that shortening the barrel on the muzzle side of the gas port does not matter.

[1911crazy]

As long as the distance from the chamber to the gas port doesn't change your ok.  You just need to do a recrown at the muzzle end.  The better the crown is the more accurate it will be.


Accuracy wise;

My saiga's have 16" barrels and there in 223 and 308 and there very accurate out to 100yds and some are hitting gongs at 400+ yds too.  So short barrels can still be very accurate too.