A 3" gun should cycle both 2 3/4" and 3" shells without fail. It "may" be that the follower is binding a little in the magazine tube or the magazine spring is a little weak. Might want to try loading the magazine tube to capacity and seeing if it cycles them all or if it is just the last one hanging up. If the first one cycles fine then it isn't the shells. A way to check, once you get the gun back, is the push on the follower and see how much spring tension it has or if it acts like it wants to bind.
Sometimes cleaning and applying a light film of oil to the inside on the magazine tube will help with feeding issues
Last edited by Big Pard; October 29, 2012 at 08:13 PM.