You certainly could mount an ACOG type sight on it, there are also many AR-22 type optics offering .22 BDC reticles ( Burris comes to mind), but realistically if you are just plinking with it any red dot will do the job. I guess it all depends on what range you plan on shooting at on a regular basis, cqb distances don't really need more than a red dot, if you want to stretch it out farther than that then an AR-22 scope might be the way to go. My buddy has been running a GSG15 in speed steel for a couple of years with a cheap $80 Chinese holosight( eBay) and it has held up no problem to the .22 recoil and is surprisingly accurate