This is a Mosin Nagant 91/30 purchased new-ish from Big5 in December. I've already cleaned it with break cleaner, taken a 12 gauge bore brush mounted to a drill etc... the bore is clean. The issue I'm talking about isn't in closing the bolt, it's in sliding the bolt to chamber a round. It's hanging on the mechanism that holds the rimmed cartridges in place. (I've heard it referred to as the magazine interrupter.) Here's a video I found that talks about it, but not specifically about my issue. https://www.youtube.com/watch?v=axDWSWvoPao If there are no rounds in the magazine it cycles just fine. (Same if I take my finger a depress the rounds down into the magazine.) It works intermittently, which only serves to frustrate my poor son who got this rifle for christmas Is there something I can trim/polish/adjust to allow it to consistently cycle?