I used the method Daivid Tubb's recommended (suppressed or un-suppressed) to tune the gas block on my MSR-10. Get the ammo you will be shooting and load the mag with one round, close the gas block all the way off and then open 4 clicks (YMMV), fire the weapon off a bench and see if the bolt locks back. If it doesn't continue by opening the gas block one click, fire round, and check for lock back. When it does lock back, load three rounds, and fire with the weapon shouldered while standing. If it cycles all three rounds and locks back add one click of gas (to allow for carbon, etc.) and call it good. If it doesn't, add a click at a time and repeat until it does. Should be good to go at that point! Un-suppressed my 6.5CM needed about 14 clicks to run right. Suppressed? I'm guessing half that but I'm still waiting for it to get out of jail...