Personally, when brand new it would shoot 00 buck with no problem. #6 high brass bird shot would cycle about 70 to 80% of the time. Cheap old 12 gauge #6 low brass would cycle about half the time. The half the time the old junk would cycle was when I was really leaning into it like they taught me in LE. In the military I suppose they told us to lean into it as well, but it was so long ago I would not swear to it.