If going 18"+, I'd go with a rifle length gas system. You can also use an adjustable gas block like a lot of guys here run, or without an adjustable gas block and just run an H2 buffer, or something in the 4-4.7 oz. weight range. You could also use a captured spring system like JP or the Armaspec stealth.

Originally Posted by raybass
I try to stick with the basics, they do so well. Nothing fancy mind you, just plain jane will get it done with style.
Originally Posted by Pharmseller
You want to see an animal drop right now? Shoot him in the ear hole.

BSA MAGA