Originally Posted by ICANHITHIMMAN
Thats cool but it seams like the brass would build up and jam the action from the bottom
The 5.7x28 brass is about the size of 22 Mag brass. The 30 round lower mag will hold 50 cases since it has no spring or follower. A lot of room in there. Just dump the brass catcher each time you change the 50 round FN mag. It won't hold 100. It will jam if you try to shoot the rifle upside down.
Repeating rifle designs which don't drop brass have been around a long time like this in 45 LC.