SPAS-15 actually uses a 6 round magazine (it doesn't get more authoritative than the Manual ), though I am not sure if it is capable of 6+1 or if Sir-Tech was just fudging the numbers to minimize magazine items. EDIT: few more minutes of searching, and it looks like it can block feeding from the magazine to have one more round loaded (ie. special round like tear gas or the like), I must go back to being productive now.