In my younger days i did combat shotgun shooting at the gun club i belonged too..by the way, i'm in Ontario...my 870 pump gun had an extension mag on it and i could hold 10 rounds with 1 in the spout...as it was a pain in the butt to change mag tubes i just cut a wooden dowel to fit and when i hunted it could only hold 3 in the tube and 1 in the spout...the Conservation Officer stopped us one day and about ####t his drawers when he saw my pump gun...he took it from me an ask for 3 shells...i gave him 4 and said if you can get them all in you are a better man than me...when he realized that the fourth shell would not go up the tube he asked me why i had such a large mag tube on the old pump gun and when i told him he said he'd never heard of combat shotgun shooting..now we are talking back in the early 70's when this sport was not widely appreciated...as he lived in the general area of our club i invited him to come out and view a match which he ended up doing...he was impressed and thanked me for enlighten him and he asked me where i purchased my tube and did it come with a plug to which i told him where i purchased it and that i made my own plug...as the vp of the club was present I introduced him to him and informed him that the vp also owned the local gun store where i bought my mag tube...bottom line is, if you are using it for anything but hunting you can put as many shells as your tube can hold!