A video I recorded a few months back looking at several Sheridan valves that I had sitting around.
Top valve is a stock Sheridan valve that was likely used with small changes in EB pistols and pump paintball markers built for PMI for several decades.
The two center valves are Palmer’s Pursuit Shop Valves. These are cut with only a straight through center channel, which allows them to run with better efficiency at high pressure. These valves are used on Palmer’s semi Automatic and pump paintguns such as the Super Stocker, Houndstooth, Hurricane, Paladin, Typhoon and Stroker.
A cut on the bottom of the brass body is also required so the channel can be indexed with the air passage through the body to the bolt. One thing to note on the two palmer’s valves shown is that the valve on the left has had the lip cut down. Which is likely a homemade modification.
The bottom valve with cup seal is a Sheridan PMI Turbo valve, manufactured (or modified by Airgun Designs). These were released in 1988 or 1989 and were meant to increase efficiency.
Sponsored teams, such as Farside, Lords of Discipline, and the PMI Piranha’s used the PMI Turbo valve in their Long Barrel Piranhas with both constant air and 12 grams. The Lords of Discipline used these valves in their Piranha Long Barrels with Micro CA IIs and 6 Pack Changers to win the 5 man and 15 man Lively Masters (Line SI Manufacturer Masters) in 1989.
All these valves can use stock Sheridan cup seals.
Find Sheridan parts on baccipaintball at http://www.baccipaintball.com/parts/pump/sheridan.html