I got some shop time this AM, and further refined the setup. I mounted my 92/4500 with a dynaflo reg so I could finetune the input pressure, and also have a little more tank capacity. As a bonus, this tank tucks more tightly under the stock.
I used a spring with 3/4 of a coil less length. I also relubed the hammer with AKA
super light oil. I tried a little something new as well. The bolt is an ACP bolt with no orings. I rubbed some graphite lubrincant into the bolt everywhere but the ball contact areas. It seemed to hold nicely in the light grooves left from the lathe. After reassembly and testing, the input pressure from the Dynaflo is set to 780PSI., I was able to cycle the marker reliably down to 400PSI. The marker is shooting 260FPS at that setting. I then turned the pressure gradually upwards until I was shooting 290-295 every shot. That put the pressure at about 510 PSI
(sorry for the grainy shots)
The marker shoots VERY well with this setup. I can honestly say it throws as good of a ball as my DM5, just at a slower ROF. The reduction in operating pressure greatly reduces the violence of the hammer inertia. She still rocks, but the weight of the setup and the lighter recocking forces makes it a gentle sway instead of a harsh buck.
I believe that this is quite possibly the ultimate in paintball technology. The very pinnacle of the pneumatic arts. Oh sure, you can get things lighter, more efficient, more BPS, more whatever. But the feeling of raw power this marker gives to those mighty enough to wield it more than makes up for anything else those "other" markers can give you. I plan to top it off with a milled aluminum feed elbow I saw somebody is swinging on Ebay. It seems more appropriate than plastic on this overengineered heirloom of paintslingage.