Originally Posted by Spider!
It isn't necessarily bad. You can get good efficiency across a wide pressure range as long as the valve, springs and marker match up to the set pressure. 500 psi can have some temperature advantage since the gas doesn't drop as far across the regulator like a 300 psi set up will.
From over bore to "match" bore, I often see a 30 fps increase. I start out testing a marker with an old over bored barrel to see if my set up will be able to play with very undersized paint. It has been noted that match boring sees the most inconsistency in the paint, but I don't get to set up for tight boring very often.
Chrony and count your shots with an overbored setup. Then drop your velocity 30 fps and count again. That will give you an idea about what your bore (only) will do for you. On a 500 psi poppet, I would think you could use a 12 or 10 inch barrel. As pressure gets lower and shot gas volume goes up, you can get more velocity (and efficiency) out of a longer barrel. Long tight barrels on high pressure start to trade off at some point, but extra barrel length is not as bad as "not enough".
My concern with the set-up im running is that pre2k valve chambers are designed for high pressure and low volume. I feel like by using a regulator im trying to "swim upstream" if you will and making the marker do something it wasnt designed to do.
I have a spring kit coming in this week and im hoping to experiment. Any advice on where i should start. Im getting a madman spring kit. Im trying to decide on either a hard valve spring or a medium one.