Back in February on 2016 I wrote about my then-new (to me) FWB LP80, the most accurate spring air pistol ever made. Mine arrived with a Beeman-installed scope rail that I removed, leaving holes:
that I filled with setscrews. As I’m now shooting my more recently (April 2017) aquired FWB LP100, the LP80 has been sitting 9in the pistol case untouched. I decided to mount an optic and perhaps use it for NRA Bullseye practice. The problem was finding a set of rings that would engage the recoil lug recess at the rear of the mount. Most rings I tried didn’t work, as the recess is so far to the rear of the rail that there isn’t enough rail behind it to support a ring. But way back in the rear of my scope mount box was a long discontinued B-Square mount I bought back in the 1980s. If you look at the photo at the top of this article, you’ll see that it hangs way over the rear of the scope rail- but it’s still solidly mounted.
The recoil forces acting on the moving part of this recoilless pistol are actually pretty violent- the receiver only moves a short distance, but it’s very light, and the movement needed to counterbalance the forces exerted by the spring and piston is sharp and rapid. When I tried to mount a scope using rings without a recoil lug, three shots was all it took to dislodge the rings from the rail. I mounted a Millet SP1 for my test, as it’s a pretty rugged sight given that it sell for around $50.
I shot it this way for a few days. While it worked well, and was accurate once zeroed in, it made the pistol a bit top heavy, which I didn’t like. A lightweight mini-sight might be a better choice. I removed the sight and mount, replaced the set screws, and put the LP80 back in the case