mag tube follower all the same inside diameter? 12 ga.? so followers are generic? eccept for the length correct? on another note magazine clamp? one that doesn't marr the finish and stays tight Nordic doesn't fit the 930spx because of the choate extention differing in diameter? what something to stay put but not break the bank. Remington 870 mag clamp? not in the market for a plastic or polymer. I can tell by some of the prices that a lot of maufacturers are very proud of their product. does Mossberg sell a clamp themselves? thanks in advance Mossberg nation. the oldman.....