Some experiments and fiddling with a 45

[sevorg]

I've just embarked on stripping my unmodified .177 HW45 to degrease, deburr and reassemble with non-combustible lubricants. (While it's in bits if anyone would like any measurements taking of any internal components please let me know.) I've owned the pistol from new and it has fired around 1000 pellets in this time.

An update on my 45 fettling.

The original pistol, untouched, was producing the following ftlbs energy
Superdome 4.37 +/- 0.12
JSB exacts 4.90 +/- 0.17
R10 (7gn) 4.85 +/- 0.09

After stripping, deburr, selective polish and relube with dryslide etc
JSB exacts 5.00 +/- 0.10

Next the spring guide was reversed (opposite end to factory fitment)
JSB exact 4.66 +/- 0.19
It was noticeably smoother to cock which I put down to the spring not buckling as being supported along its full length. Power was down 0.34 ftlbs and recoil was subjectively lower.

Pistol was now stripped and a new, custom airseals piston seal was fitted, unmodified and the spring guide returned to the original position inside the piston. After 50+ shots the following powers were measured.
JSB exact 5.56 +/- 0.20
R10 (7gn) 5.44 +/- 0.09

Final mods were to size the new piston seal to be an easy sliding fit in the cylinder, added a thin steel piston liner and a 1mm thick washer inside the piston for the spring to seat on and retain the piston liner. As good power was being made with the previous tests I decided to assemble with the spring guide reversed to give the smoother cocking and recoil characteristics. Another 50+ shots were fired and the following powers were measured.
JSB exact (8.44gn) 5.28 +/- 0.15 (532 ft/s)
R10 (7gn) 5.15 +/- 0.05 (575 ft/s)
Mosquito express (7.9gn) 5.27 +/- 0.07 (548 ft/s)
FTT green (5.5gn) 4.82 +/- 0.15 (628 ft/s)

I'm now very happy with the refinement and power levels of the 45 and see no point in taking the testing any further. The power will almost certainly increase further if the final setup were to have the spring guide fitted back in the original position, possibly around 5.6+ ftlbs but at the expense of refinement.

For reference, the original components weighed in at:
piston and original seal = 102.3g
spring guide = 22.3g
spring = 54.3g
original seal = 3.0g
new custom seal = 1.6g
new piston liner = 2.7g
new steel piston washer = 1.3g