Barrel choices

[Twiztids4]

Thanks for all the info gentlemen. Has anyone ever used an Adam Arms piston conversion kit on their Grendel? I used to have a complete AA upper and loved how clean it ran. Didn’t know if it would run good for a grendel. Also what gas. Also what gas black do you guys prefer? I’ve always been a non adjustable guy but lately I’ve picked up a few bullpups that required them (RDB and RFB) and they are pretty sweet. Superlative seems to have a new “Bleed off” style that is very similar to Keltecs and it seems like that would be the way to go if you were going adjustable.