I have a 995 TS that I have fired around a thousand rounds through. I like the carbine, it is a lot of fun to shoot and has been reliable if I load the magazines correctly. I put a Weaver 1x3 scope on and zeroed it at about 25 yards. It held zero well on the plastic top rail with the aperture sight removed until I cleaned the rifle. The weapon seems to benefit from the judicious use of quality weapons grease at wear points. I went to the range to have some fun and found that the sight was off paper at 25 yards. My question is do you find that you need to zero the carbine after disassembly? Should i replace the plastic weaver rail with aluminum picatinny rail? I also removed the plastic bottom rail.