You are 100% sure its back together right after removing the plug? If you try and put a 4th into the magazine how far does it go?
Steve

 

I’m almost positive it is. Removing the plug is really simple with the CZ. All you have to do is unscrew the magazine tube cap and pull the plug from the hole that’s at the end of the tube. With the Federals I still have about 1/2” of the brass head showing, with the Winchesters I only have about 1/4” showing.

 

A couple of reviews on the CZ 1012 web page help set my expectations. “I purchased the Grey 1012, right out of the case it ran 3″ magnum steel shot and light target loads without issue. The gun points great and is well balanced, action is smooth and the gun is very simple which makes cleaning quick and easy.

 

I'm having the exact same problem as Khyden. Anyone know the method for opening up the tube to check inside?

Thanks

 

I have no idea if this will help but will toss it out there. I have an old 20 ga. 1100 magnum, I haven't used it for hunting for years so I replaced the 28" barrel with a 20" rifle sight barrel thinking it would be more useful for HD in that configuration should the need arise.
After installing the short barrel I tried loading it to full capacity using buckshot loads and had the same problem, gun would only hold 3 instead of 4, no plug in the magazine. What I discovered was rust build up in the magazine tube was stopping the follower from full travel. After cleaning of the tube and application of oil problem was solved.

 

I have no idea if this will help but will toss it out there. I have an old 20 ga. 1100 magnum, I haven't used it for hunting for years so I replaced the 28" barrel with a 20" rifle sight barrel thinking it would be more useful for HD in that configuration should the need arise.
After installing the short barrel I tried loading it to full capacity using buckshot loads and had the same problem, gun would only hold 3 instead of 4, no plug in the magazine. What I discovered was rust build up in the magazine tube was stopping the follower from full travel. After cleaning of the tube and application of oil problem was solved.

Thanks, mine is a new model, but still worth trying. I'll check it out