I'm sorry, I should have been more descriptive. The magazine stop isn't working in that it seems to be stuck in the detent groove, allowing the shells in the magazine to all squirt out while being loaded. If one is careful, it can still be loaded, and functions fine after that, but loading can be tricky.
Lloyd, The more I reread this the more convinced I am there is nothing wrong at all. When loading a 12 or 42 with action closed the cutoff does not engage any shell rims. Only the closed shellplate/bolt projection keeps them in the mag tube. This is normal. So, yes, all the rounds can spit out if you depress the shellplate (or are a bit ham-handed while loading - like me).
The purpose of the cutoff is to stop shell #3 (#1 is in chamber, #2's rim is being held by the bolt projection and shellplate) from interfering with the shell (#2) about to be fed. Thus, the cutoff engages only when the action is being cycled. Competitive skeet shooters sometimes used to remove the cutoff, as they are/were only allowed to have 2 shells in the gun. In that situation the cutoff is not needed.
Your last sentence kinda tells us the gun is operating as it should. I have had real cutoff problems - on cycling the gun it would dump shells on the ground. Doesn't sound like this is what's happening to you.
Sam
