WY-
Those are Sumatra mags pictured. The question was about the rather new Eagle Claw. It has a box style magazine spring loaded, self-indexing. Later upgraded EC mags did add the central oring like you pictured, I presume to help with the slug situation. Slugs lack the oversize skirt pellets have so any proper size slug in theory could go through the same size hole the pellet probe goes through. A design compromise is the magazine oring tension is slight to allow pellets to be loaded skirt first without snagging. Then if you load slugs, point the muzzle skyward and jar the gun jacking the underlever gravity wins.