I just got my Project Arms (Stan's built) DT and he has a striker system(like the semi RPD's) and it worked very good. I like the striker systems vs the hammer ones for these types of semi converted type guns. It fires military surplus ammo, semi firing pin is very thick(will not break), he is a master welder and machinist. He is working on a DPM (exact same semi design) for me(yes I've waited 2 plus years) which he says I should get within a month. He built a MK3 Bren for me also that was done very well. It had some minor issues but they were dealt with and it works fine. I waited for them but I knew and expected it. The hardest part for the MK3 was getting a good barrel for it but I turned to my old standby master machinist Penley and as usual he exceeded my expectations. I just feel that talented, perfectionist people deserve the praise.