For want of a better term. I bought a 77-22 Hornet, the gray All-Weather model from a friend. It's a great rifle and shoots very well. The first thing I did when I got it home was to clean it, or try to. After 3 online purchases I finally found a bore guide that fit. There was (is) a little hook shaped doohah in the left side of the chamber that the bolt slides over but won't allow your typical bore guide through. I did not get any Ruger booklet or paperwork or schematics with the rifle. Does anyone what this doohah does? Thanks.