My Model 15-4 has developed a bit of an issue... A bit of a burr has developed around the hole where the firing pin pokes through the frame. This burr will frequently catch on the head of a cartridge and either prevent the cylinder from rotating, or just make it really difficult. My question is what to do about it. I could take the burr off with a file or dremel, but is it just going to happen again? It's gotten to the point that it's not really shootable, so I need to either fix it or drop it off with a gunsmith. What say you all?