Hello, new to the forum and a new 91 owner. It runs fine with the factory fixed butt stock, but I bought a surplus collapsible butt stock [I have loved the look of these since I was a teenager] but the recoil spring guide ring on the collapsible stock is too wide to enter the bolt channel. Okay, do I try to find a replacement ring, and if I do, do they come in different diameters? Or do I try to sand the existing one down a bit? Or Three, just run it without the ring? Thanks