Alright so I was getting frustrated with my shotgun concept. Someone else can perfect it. I decided that after being asked if my old UMP-45 was worth building that it could probably use a tune up. So here's the new one. It's very similar to my old one but there are two main differences. First off, the barrel is longer. My old one was probably a tad too short. I have a feeling this one is too long but you can't really make one in between without getting complicated and it's pretty comfortable this way. The second main change is the barrel and firing pin. I used a hybrid type barrel using both a rod and connector barrel so that the ammo can fit through but so that the pin won't wobble. The firing pin uses the concept from my shotgun to be like a charging handle. It's a little further back but this was so the pin wouldn't fly out and I didn't want to move the trigger up + back barrel up.
Sorry, I didn't bother taking a picture of the stock. I just made a quick, crude wire stock because I didn't have the pieces to make the full one from last time. I was hoping someone else would be able to take the gun and add a folding stock for me. I'm still working on the handle and thinking about changing the trigger guard because it'll get in the way of the trigger unless you hold it down. Finally I have to test the reliability of this gun. After all that, I'll post it. I'll get a video tomorrow if I get the chance. I might be going out of town though.