Oh oh... serious problem with my TM shotguns!!
 

Ok heres what happend. I bought two used Marui shotties (spas and m3 shorty). Both were shooting fine at first, but after their first field test both had the same type of problem. the pumpgrip would just slide down instead of cocking the spring. there was no resistance. besides that u could not pull the pumpgrip all the way back up to its original position.
after removing the shell and shaking the gun quite a bit, bullets would fall out and the gun would work again...

so far so good, yesterday both guns jammed right from the start, showing the exact same problem as stated above and now I couldnt get them to work again.

I have a really bad feeling about this, but maybe not all hope is gone. Is there anyone who had the same problem?
I can go and take pictures or try to explain more precisely whats happening if u can tell me what i need to look for.

PLZ HELP!

With the Grip not going back, sounds like a jam. My shoty does that sometimes if I pump it twice accidentally. Just take the cartage out and try to clear the barrel of bb's. Maybe there is something wrong with the shell and it is just letting all the bb's out and jamming it? Lube them up and keep trying.

Sounds like the same problem

The strange thing is this:
If you mean the gun was unloaded, you tried to cock it, and it wasn't pushing the spring back, then that's a pretty major (and rare) break in the piston assembly.

What generally happens is (with a loaded shell inside):
-Pull back the pump
-Spring is compressed
-Bb's move up into the three barrels
-A fourth one will slip in and sit in the middle of the three nozzles
-You push the pump forward
-The trinozzle moves forward and the fourth bb is forced between the nozzles, usually deforming them

In that case the pump generally will not lock forward, allowing the pump to slide back lose, as you described. I think you'll end up having to get a new nozzle just because it'll keep jamming up on you otherwise.

Anyways, sorry for the diatribe, but I hope it helps you. Feel free to PM with any questions...

M