So I did some more research about the inside of many air cylinders. They are not polished to the same level of finish as on the outside for obvious reasons. Anyway, I followed this Robert Lane video on Youtube that he has on his site....
And and then this one on slow leaks.
All related of course.
So I got some p400 then p800 grit wet/dry paper and then made a small drum I could chuck in my battery powered drill, and I honed out the area above the cylinder threads that the reg barrel sits in starting with 400, then finishing with 800grit. Then I flushed everything out with brakeleen, dried it all out and re-greased and refitted the reg. I filled to 3000 psi, then did a 60 shot string, averaging 858.9fps with a high of 871.5 and a low of 823.4( which btw was shot 60) the string dropped off the regulator at shot 54 with a velocity of 849.6, then dropped steadily down with 845.3, 838.4, 840.3, 833.3, 836.5, 823.4
shot 50 was still at 860 fps. So consistency wise, this gun doesn't miss a beat, and having a 50 shot capability is awesome. I re-filled the air cylinder to 2000psi to get it back into the regulated pressure and I will let it sit overnight to see if the honing out of the air cylinder has made a difference. Fingers crossed this time it works. Failing that, I may need to look at a slightly larger O'ring again made from softer material that can fill imperfections better. I am certain it is the main seal that is the culprit.
