May evolve into a project other than what I was hoping for.
Anyway, the Powermaster 66 tube is a little longer than a 760 tube, and with the linkage you will get a little more stroke
Pellets don't like to travel at over ~850fps before they become unstable..
The tube for the Powermaster 66 (and the Recruit for that matter) is identical to the 760 tube in all ways except length ( about 1.5 inches). [...] It's a direct bolt-in replacement.
BTW, 800 is pretty good i'd say.. how many pumps was that at though? did you put in a flat piston? I was able to get over 900 fps from a 1377 with ft piston, 24 inch barrel and some other little changes, at "just" 20 pumps