Is This Normal for a QB78?

[tolly]

Hello, i just reassembled my rifle today, but i havnt actually had a chance to put some co2 in it and fire it as i dont have any at the moment.

When cocking and firing the gun with no co2 in it and looking down the co2 tube at the same time the piercing pin doesnt actually appear to be moving when i pull the trigger!

Is this normal, does the piercing pin only come out when the tube's pressurized?

cheers, matt

[RCnMo]

I haven't actually looked down into mine. The piercing pin is spring loaded so as to leave a passage way for co2 to enter into the valve body. When the hammer strikes the valve pin, it's body should come forward just a tiny bit to pierce the co2 powerlet. I would assume that there is a very minute amount of movement with the piercing pin. You could probably check it with a small wooden dowel about the size of the neck of a powerlet. You could place it in the hole and fire your rifle and see if you end up with a dent on the end of the dowel. If it doesn't seem to be working, you could either wait until you get some powerlets or disassemble the rifle and make sure that the piercing pin is lining up with the hole. It needs to be able to plunge in and out of the hole without hanging up. If you disassemble it, you will have to replace the seals throughout the rifle. There are 3 o-rings on the barrel which get cut very easily when disassembling and reassembling and there is a seal around the valve body itself. The valve body o-ring is a special material and you can't use nitrile. I used viton and have been told that it wouldn't hold up. So far, it's been in there for 3 months under co2 pressure and is still holding it's charge.

[ribbonstone]

..when looking down the gas tube.  that piercing pin is spring loaded...it jumps in and out as the valve opens and closes...not likely to see it move when looking at it end-on  and down a metal tube.

[mikeiniowa]

The basic stroke for the pin is around 5/32 of an inch, not to easy to see when looking down the tube....