I put a nelson kit in my Sniper II, but it was a Belsales knock-off and the worm-drive adjuster didn't work at all. I had to drill the body to get it to work in the first place but decided it wasn't worth messing with and wanted to go back to the Sheridan spring set-up. I ended up using the hammer from the Nelson kit (smooth, adjustable from the top) with the Sheridan IVG and spring. Worked out great.
If someone doesn't mind using springs to adjust their velocities, they can have that Nelson IVG for the cost of shipping.
Bleeding Paint and Sweating CO2 since 1988!