Originally Posted by Rockfrog
the offending o-rings size is -010 Urethane D90 ... I've used regular Buna replcements from home depot and the sort as well (they just don't last as long).
Part# 29 valve face o-ring
I just recently had gotten some o-rings from Paintball Solutions for my Delta .68. At my work we have a huge selection of o-rings and the -010 does not match up. We ended up using a caliper to figure out the size of the o-ring. The o-ring seems to be a metric o-ring and not a standard. How metric o-rings work is you measure the thickness of the o-ring and the ID not the OD like on a standard o-ring. It seems to measure 2mm thick 23mm ID. I do not think you will find this size in a Home Depot/ Lowes, but McMastercarr has them. I hope this helps.
P.S. I asked Paintball Solutions what size it was and they did not seem to know.