RE: Nylon 66
The back sights are prone to breakage infact I have on in the shop now with a broken one that someone decided to over tighten. They are grooved for 22 rings to mount a scope easily. The one that said he had a stainless/ black version, is actually nickel finish? And take heed on the advice about taking them apart, they are a Pain in the A** to put back together if you don't know what you are doing. And MORE IMPORTANTLY "NEVER USE ANY SOLVENT" on these rifles inside or out. It will flat eat up all the plastic parts. So be very careful when cleaning these rifles.