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sscoyote · New Member

Anybody know if you can get a 177 pellet to 800 or 900 fps (accurately) out of a pistol configuration?

Robw · Veteran Member

I am getting 837 fps average from 15 pumps with this pump up and the
accuracy is, well, Lothar Walther precision.

-I added a Lothar Walther 18.5" barrel (I also have a 16.5" smooth bore BB
16.5" barrel for it).

-It has a 1985 brass compression chamber (Crosman=valve) with lighter
valve spring, reworked with angled exhaust port and narrowed exhaust valve
stem.

-90 durometer O-rings throughout.

-True two stage trigger with 1.5 lb pull weight.

-Crosman steel receiver (Crosman=breech)

-Modified main-tube to accept new style hammer and charging pin.
This got rid of the separate charging (cocking) knob and allows the
bolt to charge the pistol.

-Polished the inside of main tube, hammer, bolt and inside of receiver,
trigger contact surfaces.

-All springs coated with Teflon Velocity Tar.

-Stainless steel fasteners.

-760 barrel band.

-0.5 mm longer piston for reduced pump head space.

-20 grain heavier hammer.

-Hammer spring preloaded 3 mm.

All parts were coated with Moly/Graphite lubricant and it gets better
pump up and velocity if I lube it each shooting session with Castrol
10-50w full synthetic motor oil. It seems like the detergent action
of the oil keeps the gun cleaner than with Pellgun oil too.

There is another individual here that claims he achieved supersonic
speeds with one of these. So this one most likely doses not represent
the maximum that might be achieved with one of these little pumpers.