I KNOW, it looks a lot like a Saiga 12, but it's not
This shotgun features a 10-round magazine, an easy take-down feature, is gas-operated, and is select-fire. It features the AK-47 style mechanical principles.
TO USE: cycle action, select firing mode (middle is auto, down is semi), and fire with enter/return or trigger.
TO TAKE DOWN: push upper receiver retention tab in, and quickly lift the upper receiver. hinge it about 15 degrees, and remove it by pulling it back. Then, remove the recoil spring, then the bolt carrier.
EDITS:
made gun less likely to fall apart during firing
edited ejection pattern
added a magazine with slug ammunition