more pics to come, when my cable modem stops flipping out on me. for now, those screws are 20mm and 25mm, both m4x .7p and 5mm. Make sure the 4 prong t nuts are metric the right size, of course. Ace has it all labelled. I got the weaver rail at wally world, i believe the hole positioning is pretty much standard. Again the holes line up exactly, just take your lower and eyeball it. figure out where your grip is going to go ahead of time before you do the mount, the first time i did it i put it too far back and i couldn't get a mag rocked in. When I screwed into the mounts i took it easy because those prongs will probably collapse unless you figure out a way to make slots in the lower for the prongs to stick into. don't worry, there is plenty of clearance to the bottom of the barrel so you're not going to get direct contact heating. A little blue thread lock should keep em from backing out.