For anyone else who couldn't find the answer to why a 7 round magazine tube on an M4, and probably the other products as well, couldn't fit 7 rounds - I could not understand why my new M4 LE model with a 7 round tube would not hold 7 rounds of my Federal 00 Buck or Slug rounds - I checked for a limiter (which there shouldn't be one as it is a LE model, or any other blockage or obvious cause.  With a well-hidden reference on the internet about 2 3/4 inch shells being slightly different lengt