I just bought a NIB PS90 Triple Rail (black). I mounted an inexpensive NcSTAR holographic optic with 4 dialable reticles. At a mere 15 yards, I was struggling to shoot tight groups. The groups were walking on me, right to left. I tracked it down to me not setting the windage set screw properly. By the very end I shot a few tight groups, but I need to test further to build up confidence. Very fun to shoot, but I was expecting a tack driver.
When I field stripped, I noticed some play between the barrel shroud and receiver. A few degrees of rotatory play and a slight knock. I expected this to be more soild. Is it normal to have a little play here? This is not the cocking mechanism I am feeling. The barrel is tight to the shroud.
I was able to reduce 95% of the play by wedging a folded aluminum shim between the flat of the barrel shroud and the front of the receiver. I will test fire tomorrow to see if the shim falls out (I don't think it will) and to see if it improves accuracy (I think it might).
Like I said there are at at least two possible factors: sight drift (I think the windage set screw is now correct), and the play between the barrel shroud and receiver (now shimmed).
Edited: the barrel play is apparently a normal design feature and shimming is NOT recommended. I removed the shim before further test firing. My accuracy problem is probably related to my not tightening the windage set screw properly. I found that I need to push the rear of the sight body to the left against spring pressure while tightening the set screw. Once I did this, the last group was a one hole group at 15 yards, but then I ran out of ammo. More testing is needed. If this does not improve accuracy the next step is to invest in a quality optic.
When I field stripped, I noticed some play between the barrel shroud and receiver. A few degrees of rotatory play and a slight knock. I expected this to be more soild. Is it normal to have a little play here? This is not the cocking mechanism I am feeling. The barrel is tight to the shroud.
I was able to reduce 95% of the play by wedging a folded aluminum shim between the flat of the barrel shroud and the front of the receiver. I will test fire tomorrow to see if the shim falls out (I don't think it will) and to see if it improves accuracy (I think it might).
Like I said there are at at least two possible factors: sight drift (I think the windage set screw is now correct), and the play between the barrel shroud and receiver (now shimmed).
Edited: the barrel play is apparently a normal design feature and shimming is NOT recommended. I removed the shim before further test firing. My accuracy problem is probably related to my not tightening the windage set screw properly. I found that I need to push the rear of the sight body to the left against spring pressure while tightening the set screw. Once I did this, the last group was a one hole group at 15 yards, but then I ran out of ammo. More testing is needed. If this does not improve accuracy the next step is to invest in a quality optic.