Mix-n-Match
This is an over simplification, but think about .22 rim fire rifles: Typically the ones with detachable box magazines will feed only .22-Long Rifle's. But, the ones with a tube magazine will usually feed .22-Shorts, .22-Longs and .22-Long Rifles in any combination. Most shotguns with tube magazines are the same, the size given is the maximum, but you can mix in shorter ones.