Knex Shotgun Prototype (uses Shells)

So this is the shotgun ive been working on for awhile now. It fires pretty good with what i think is a 64? and not bad with strung together 32s. and its pretty basic you take a shell pull back the ram insert the bit sticking out into the barrel and lock it in. and it has a nifty feature that came around by accident. But when you disconnect like 2 rods in the back the top comes up and you can switch barrels i guess id say. Because i was working on making a mag fed one for it but it failed so i might use a mag shell type thing.

Things it has now
-trigger holds the ram pretty far back
-its pretty sturdy
-pin guide
-stock
-and it uses killerk's shell design with a few tweaks to work better.

Things im working on
-some way to store the shells
-mag shell(if that makes sense)

So tell me what you think of it and anything i could add/improve on it!