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Re: Mods on the valve...

December 6 2017 at 7:31 AM
Ronald  (Login GunNut10)
Crosman Forum Member
from IP address

Response to Mods on the valve...

The steroid mod focuses mainly on beefing up the pump arm along with some valve mods.
There is a lot of performance to be had in the valve along with a FT piston and valve.

A steroid pump arm and a FT setup and other valve mods should yield around 950+ FPS with 14 pumps.
That is using 14.3 CPHPs.

I got 960 FPS with 15 pumps, same valve, 7" x .750" stroke with a reinforced 140 pump arm.

My MK based gun gets 791 FPS with an 18" choked LW barrel on 15 pumps.
It only has a 4" x .750" stroke, about 55% of a 392.
Longer is not better as the tube starts to flex as length increases.

Some steroid numbers:

CPs 14.3 grn:
4 pumps 565, 569, 563
6 pumps 658, 658, 660
8 pumps 728, 732, 731
10 pumps 762, 778, 772
12 pumps 814, 819, 814
14 pumps 840, 841, 840


This message has been edited by GunNut10 from IP address on Dec 6, 2017 11:29 AM

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