Any thoughts on what you may or may not know? On automatic(bar or similar) vs ar style(gas length vs gas port size) effects. With + 1, 2 and 3" rifle length that is sometimes a failure? Example: I have an AP 6.5cm 22" barrel w/standard length rifle gas system and it functions perfectly with factory ammo, but PR +2 with same ammo is a bust! Now I also have a CBI and Faxon standard rifle length system that pops primers with the same factory ammo. I haven't varified port size for any reference and haven't tried using a h2 or h3 buffer yet. The local gunsmith moved so I don't have anyone close to check or open port size up. Lots of food for thought.