Pump mag issue

[PrimoRocker]

On my pump mag, it'll leak a little down the barrel after fired, but then seal after I cock it back. It has a classic valve with new on/off seals. I'm thinking the on/off pin is too short? how should I fix this?

[Ando]

More then likely your PT spacer. They usually need to be changed out when going to pump but you can always see if it's the on/off by holding the trigger back after you fire it.

[PrimoRocker]

More then likely your PT spacer. They usually need to be changed out when going to pump but you can always see if it's the on/off by holding the trigger back after you fire it.

Do you know if I go bigger or smaller for the spacer? holding the trigger does stop the leak

[athomas]

Go with a shorter powertube spacer.

Pump mags work by using the wave spring to prevent the bolt from resting in the cocked postion. This prevents semi-auto operation and requires the user to manually hold the bolt back with the pump. Mags have residual pressure left in the chamber after a shot (usually about 50psi for a level 7). The powertube oring resting against the back of the bolt stem is what seals the air passage to prevent all the air from leaking out the front. When the bolt is in the resting position in front of the wave sprng, the powertube spacer needs to be short enough to allow the powertube oring to move forward enough to make contact with the back of the bolt stem. For pump mags, use a shorter spacer than for a semi-auto mag setup.

[Ando]

.225 spacer is usually the money spacer.

[PrimoRocker]

got it. Played around until eventually swaped to 215 spacer and a different bolt.
super stoked :headbang: