KJW/Tanaka USP V1 not firing.

[pitobread]

Its KJW internals in a Tanaka Frame. It's a V1 and it uses the magna blowback system. It is an older gun.

Gun racks fine, no sticking. Everything works great except for the safety which is broken but has never stopped it from working before.

Depending on what I do the gun will either empty the mag completely in one shot, or just burst gas but the gun wont cycle. Gas is firing into the chamber that makes the blowback work but does not push hard enough to make it cycle. I am using propane, but I have tried green gas too. I replaced a bunch of o-rings but that didn't help.

I have completely taken the gun apart and degreased everything including the mag and reassembled, there is some wear areas but nothing looks broken. The only thing i can see is the mag may be missing a gasket at the very top that seals into the chamber that makes the blowback work. But I am not certain there should even be one there. It looks like there "could" be one there but I don't know. Someone who is familiar with these older guns would really help me out!


I can take pictures if you have an idea as to why it is not working or you want to see a certain area to help me figure this out.