Sure enough I checked the length of some other 2 3/4 inch shells and they were about 3/8 inch shorter than the shells in question. Thanks for the insight guys. By they way I love the gun. I already had an M1 Super 90 Synthetic field and loved it so it wasn't a contest when I wanted a tactical shotgun.
I just purchased an M1 Tactical and I can only get 6 rounds in the tube with the 7 rd. extention attached. I can get the 7th about 2/3 of the way in but it bottoms out. Any suggestions?