I acquired a 1968 336RC 3030 recently. I shot it a few time and with no problem and the did a complete disassembly and cleaned everything real good. A swabbed out the mag tube until it was real clean on the inside. I haven't shot it a lot, but I did today and a lot of times when I would be putting rounds in the tube I'd get a few in there and then the next one would go midway in and suddenly stop as if it was full. I'm wondering if the follower is getting stuck on something. I did notice when i disassembled that the sling stud mounts with a screw that goes all the way through between the barrel and the tube. The top of the tube had been shaved away to make room for this screw. It didn't go all the way through though and I couldn't see any kind of bulge on the inside of the tube in this area. I am planning to remove the tube tomorrow and see if I notice anything with the tube or follower. Any advice?