This is an updated version of my original rail. The back support has been moved forward to let the shells eject properly.
Fastened with M5x25mm screws and bolts.
Fits standard pictinny (20mm) accessories that are 10cm long.
There's a cut-out underneath the rail to clear the high profil front sight (USP .45 Match)
The .stl is not the right size. Scale it up until the lenght is 140mm long in your slicer. I had to upscale from 100% (original) to 10'000%.