Mossberg says that they will only function with 3 & 3 1/2 shells. I have heard reports that heavy 2 3/4 shells will cycle. I think it is a promotional thing by Mossberg. If you say it won't shoot cycle 2 3/4 shells, than there can be no complaints when it doesn't. I ordered one last week and it should be in soon. I will post how it shoots when I get it.