I finally got a chance to do the surgery necessary to attach the mount to the P-17. I chose the FAB Defense USM mount because it came closest to fitting on the gun's Pic rail.
The mount's rail attachment point is longer than the gun's Pic rail, and I determined that I needed to knock .3" from the back of the mount's attachment point in order for the mount to go back far enough to allow the mount's attachment screw to line up with the first slot in the gun's Pic rail. Using my Dremel with a heavy duty cutting wheel, I was able to get the material removed from the mount.
When I put the mount on the gun, it turned out that there was about 1/32" of the first slot on the Pic rail creeping into the mount attachment screw hole. I was going to try to eliminate that 1/32" from the mount's rail attachment point, but I didn't have the right Dremel attachment. In the end, it was much easier to widen the slot of the Pic rail by the amount needed to let the mount attachment screw go through the slot.
Photos below show the work done and the final product. I mounted the ADE Advanced Optics reflex red dot (6 MOA) farther back on the mount, so the balance of the gun is unaffected. I intend to use the P-17 for Rimfire Steel Challenge, so this should be a good setup. Now I just need to get to the range to sight things in.
