My Grendel build

[mateba]

From my experience with adjustable gas blocks you need a margin of space for the rail system to go over the gas block. If you have a handguard that is less than 1-3/4" inner diameter it might not fit. I used a superlative arms and a 15" ALG handguard, fits fine. So this is not as simple as putting an adjustable gas block on your your carbine. But you could put both on for $200. Replacing the barrel is just a little more. Would a 18" rifle length gas need any adjustment? http://graniteridgeoutfitters.com/Ballis...5G003P.htm