whats an older powermaster 66 velocity supoesed to be?

[bird blaster]

mine is getting an average of 538. i expected it to be more. is this normal or does it have a problem?

[johnnyfoos]

"mine is getting an average of 538."
OK, with how many pumps and what pellet?

I have 4 -66's
with number 3 at 20 pumps it has shot over 900 with 7.3gr.(only tried that twice)
The other three  all shoot less than that one
That one gets 680 with 10
the rest are getting low 600's or less with 10
and with 5 pumps they get above 500 most the time
These numbers are using a "Precision Shot" chrony
I now have two "Caldwell" units that work and have not retested these guns but
My Two P-17 have shown that shooting thru the "PS" then the other two end to end
that the numbers all are very close.
(How I found out the first Caldwell wasn't working right, it showed 98-103 when the PS showed 400-415)

Also, I live at about 4800' and mostly shoot cheap Daisy pellets for plinking
And I oil my guns with what might be to much special blend,{30 wt. ND with about 25% tranny sealer)

$0.02

[bird blaster]

10 pumps and an 8 grain hatsan express pellet. Maybe mine has a leak or somethin.

[rangerfredbob]

That sounds a little low, but if I remember right it was an older gun so the chance the pump cup is old and compressed are decent which wouldn't make as much pressure... The pump cups are only $1.15 from Crosman plus $4 shipping and that's about the only thing that could make it weak...

I haven't chronied any of my 66's, but the Recruit I built up a couple years ago I did, I made a flat top piston and valve for it along with most of the other mods I found at the time and I get over 700fps with Crosman pointed pellets at 10 pumps and one shot at ~750fps and one at ~550fps at 15 pumps... same pump tube and barrel as a 66 just a different pump handle and stock.