I'm sitting here tonight looking at a non working Benji. It has been holding air fine for three years now....just no way to exhaust it. The bolt cocks the hammer and the trigger releases it, but nothing happens but the thunk of hammer falling(maybe not hard enough?).
I took it out of th3e stock figuring I have nothing to loose by taking it apart and got to thinking "that's got to be considerable pressure somewhere" and looking at the next step taking it apart and there are two phillips screws holding the trigger assembly on beside the nut on the bottom of the tube. If those two screws come out in a pressurized gun would this end plug become a projectile?
That's a self-contained unit that even can be completely removed from the gun without depressurizing it.