I use SU22 with iron sights and AAC Prodigy suppressor. With iron sights, I have zero at about 25m. With Trijicon Reflex 2 (which I used previously on AR15 with good effect), I can't get point of impact higher than 3.4" or more BELOW point of aim. Any idea why this is happening?
Hey Oleg, Others have told me there is no problem with the SU-16 / SU-22 receiver rails, but I've had two different scopes that ran out of elevation before I could zero them - one on my SU-16 and one on my SU-22. Other optics have had suficient elevation adjustment and have worked well. In both cases, my fix was the same. I placed a shim between the lower scope ring and the scope on the rear scope ring. This raises the rear of the scope. This is the direction you need to go. Shim material should be relatively non-compressible and not prone to rot or decay so paper is out. Thin stainless foil would work well, aluminum foil works OK (especially heavy duty foil), thicker aluminum from something like a TV dinner tray would be good, or plastic shim stock (pretty much any thin plastic sheet). I used electrical tape. It was easy to use because it's self adhesive and it has worked well. It's too compressible to be optimal, but I wasn't too fussy as I'm not planning on shooting either rifle for bench rest applications. If you're good with trigonometry you could calculate the thickness you need, but I'd bet three pieces of electrical tape would be about right.
I'm not sure how you could shim the Trijicon Reflex 2, but if you had a scope and the rings were 6" apart, I figured you'd need to elevate the scope by .021" at the rear scope ring (more like 4-5 layers of electrical tape), and that's just enough to barely sight the SU-22. You probably wouldn't want to be that close to the edge of the elevation adjustment, so you'd want to jack up the rear a little more than that.
