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Alan Alford's build

2250b Tube for later move to bulk CO2.
12" .22 Caliber Barrel from Doomsday Backpacker
Brian & Assoc. Alluminum Breech with 2 barrel screws
Original site rear
Pin site on Custom Mt. Airguns Muzzle Break
2x1 Centerpoint Scope with UTG dovetail adapters
Mountain Airguns Custom Bolt and Handle
Mountain Airguns Custom Power Adapter and spring guide
B&A Boss Valve for extra Power

Built mainly for fun and to shoot at local Field Trial Pistol Match.

It currently it shoots a 14.3 Crosman Hunting Pellet at about 530 fps in a 72 degree room for 8.92 FPE.



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Well now, Some experts please chime in and HELP!!

February 16 2012 at 8:38 AM
VAF  (Login VAFarmer)
Crosman Forum Member
from IP address 165.214.14.22


Response to spraying

Gun is doing these sprayed groups, right?

But they seem to consistant in the way they are spraying.

this is a c02 or pcp setup? Liquid c02 not getting into the valve is it? I would start checking everything, and would begin with a stripdown, if you can handle it. You are saying it will do 2-3 stacked, and then 4 and five are off and to the left/right.

Chrony it. If nothing is moving around, you should see a velocity difference on the chrony.
Crosmans from a tin? IF so, get a Mic out, and sort by 1000ths. I have had Crosmans come out from .215 to .219 from the tins. BIG difference out of a barrel that might prefer a little larger of a pellet....
Nothing is clipping them when they are going into the breech area?

I would dismantle and make sure everything is clean. Check seals. Check seats. Make sure something isnt happening weird every 4-5 shots, like a valve stem/seal canted and rotating. while your at it polish it all, striker, spring ends, clean the tube, etc.....

Lap the bore while off, with some valve lapping compound, and touch the crown up. Reassemble, making sure you have a good transfer port seal.
Dont put the muzzle break back on yet...

Sorry I can't offer more than basic troubleshooting, but sometimes when somebody mentions something, you say "oh man, I forgot to check it"

Good luck and hopefully someone else will chime in and help.

God bless,

Farmer



 
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Responses

  • tune up - Dave on Feb 16, 2012, 4:51 PM
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