I checked mine and it is a 2 holer. I made sure that the gas plug was screwed all the way in then backed it out to #2 approx 1//4 turn. This does make a difference because I tried another full turn out on 2 and it started jamming more. I also left the bolt back and oiled parts and let it set for a week. This has made it start cycling med brass more reliably23/4. I tried the low brass and was mostly fte. Im going to let it set longer on an open bolt before sending it back just to try.