PUMP PISTON CUP SEAL for 13XX
This piston cup-seal is original to 1377, 1322, 2289G Backpacker, PC77, 1300KT, 760, M4-177 and similar variable-pump models.
For a few years Crosman had switched to a pump piston that used a steel pin to hold the cup seal in place. Thankfully they discontinued that pathetically bad design. This seal is for the non-pinned pistons previously and currently in use. If you have one of those pinned pistons we recommend upgrading to the newer version we have listed.