After scouring the web for info on 1377 trigger mods I seen a YouTube video about the 1701P trigger ass being a direct bolt in as long as the hammer is changed. I got the assembly from Crosman and the fluted hammer needed from a seller on eBay and all I can say is wow. So smooth and shooting at 30 yards today with JSB, RWS, H&N and even Crosman pellets it was shooting 1/2 inch groups from my Caldwel Matrix rest.