Originally Posted by
Spider-TW
I have a buna example that is documented in two different threads. The problem appears to be shelf life, not so much lube or number of shots.
At the end of March 2009, I put my EP mag into service with a quad (buna) on/off top o-ring. In May of 2012, I had a failure of that o-ring, after more than 20k cycles. Fair enough. I had bought the set of four from the AGD store, so I installed a spare and went back to play. That one lasted less than 100 shots. I found the new one had wadded up in the on/off, and the other two (unused, stored clean, out of the sun and dry) had lost their elasticity also. I dug out some ancient, unknown teflon top o-ring and a longer on/off pin, problem solved.