info on RJ machine’s riser breech

hey, i was wondering if anyone could give me some info on RJ’s riser breech… i know he countersunk the breech screw to mount the breech, but what size screw did he use? you cant buy these anymore (shame!!) so i was wondering if anyone could help out. im hopng to modify a stock steel crosman breech. also, what kind of screw is it? phillips? flat? thanks again guys! also, if anyone knows where i can geta theoben mk 4 trigger blade, that would be helpful too!!