if you notice on a lot of co2 cylinders they have a groove right where the o-ring in one of those "you don't need a tank washer" regulators have the o-ring...Interesting. You think it's just a better seal surface on the tank for the washer to seal to?
6 months old...but I'm not impressed. Been having creep problems.
for creep it's best when setting the pressure to turn the lines off at the reg, and set the pressure then, much faster response time seeing what it's actually at....