[rsilvers]

You can use Lil'Gun if you dedicate the gun to it. Basically you load the ammo until you get 1000 fps, pick a buffer - perhaps a standard carbine buffer. Then see if it locks open on an empty mag. If it does, you can call that good enough, or you can do cyclic rate testing with a FA lower and make sure you are at least at 700 rpm. If not, you can open the gas port. But then you probably don't want to shoot normal ammo in the same gun - though you may be ok if you then change to an H3 buffer.