Classic Valve Velocity Issues

[lifeincolorado]

Just got home from the field and expected to find a blown oring or other dubious source for the velocity issues that made my mag unusable today. I don't know the correct technical term, but I think it's supercharging. First shot was between 405-385. Each successive shot was lower in velocity until it got to 100fps. Adjusting reg didn't seem to make a difference. orings look good, plenty of lube, cleaned the parts to be sure there wasn't any debris. Still doing it. I've used this mag several times without issue so I know it's not a parts incompatibility. Any thoughts?

[Evil1]

Kind of sounds like a reg seat gasket. Mine did the same thing last year and I changed it out and it was fine.

[athomas]

Try the regulator seat seal/oring. This will cause issues, especially if it is old and you took the valve apart. The compression grooves need to line up or it will leak. Those grooves are created over time by being compressed between the valve halves and molded in place around the raised edge of the valve. Once you take the valve apart, if you disturb the alignment, it will never seal properly after. Therefore, you need to replace it regularly if you take your valve apart alot.