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Digitaldawn
PostPosted: Fri Feb 21, 2014 8:44 pm 
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Posts: 15
Crosmann 1322
After I filed down the screw I was able to completely bring the bolt back and the steel breech is tight now. But I still have very low power when I shoot, 255 fps.... Any ideas on what the problem could be now? I think its someone in the pump or something..
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jgoodz420
PostPosted: Fri Feb 21, 2014 9:14 pm 
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Need more info...

Are you running a flat top piston kit?

Standard valve? is the bleed hole plugged?

What screw did you file down? the rear bolt for the Steel breech?

How many pumps are you putting in the gun to produce 255FPS?

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Digitaldawn
PostPosted: Fri Feb 21, 2014 9:27 pm 
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I don't have the flat top piston kit
I have Standard valve
I don't know what the bleed hole is..
I did file down the rear bolt for the steel breech

10 pumps is giving me 255 fps with a steal breech 18 inch barrel, and hollow probe..
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blarg
PostPosted: Fri Feb 21, 2014 9:45 pm 
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Please keep a single thread going so folks aren't jumping in cold with suggestions and know what it is you're asking about and what has been tried.

If you had valve out, you may have nicked o-ring on reinstall.
If you didn't, you may have dirt in pump cup/tube keeping it from full seal.
You may have transfer port upside down (as was already mentioned in that other thread on this topic...)
Check leaks with baby powder around transfer port area between tubes when shooting.

Barrel may be out of line with transfer port.
Probe is upside down (if you can see hole in it on top when loading, flip it) or o-ring is not sealing. May feel leak on hand when shooting, but baby powder can confirm here too.

fps from acoustic chrony?
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TriggerHappy416
PostPosted: Fri Feb 21, 2014 10:07 pm 
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blarg wrote:
Please keep a single thread going so folks aren't jumping in cold with suggestions and know what it is you're asking about and what has been tried.

If you had valve out, you may have nicked o-ring on reinstall.
If you didn't, you may have dirt in pump cup/tube keeping it from full seal.
You may have transfer port upside down (as was already mentioned in that other thread on this topic...)
Check leaks with baby powder around transfer port area between tubes when shooting.

Barrel may be out of line with transfer port.
Probe is upside down (if you can see hole in it on top when loading, flip it) or o-ring is not sealing. May feel leak on hand when shooting, but baby powder can confirm here too.

fps from acoustic chrony?


Yes, what are you using to chrony? and please stick to one thread, easier to follow...

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Digitaldawn
PostPosted: Fri Feb 21, 2014 10:34 pm 
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I am using an app to crony. But I can tell my gun is way weaker after the mods because of pellet damage.. I feel air on my hands while shooting too. I need to think of something besides baby powder as I don't have any.
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Digitaldawn
PostPosted: Fri Feb 21, 2014 10:40 pm 
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I used some flower and spread it on the transfer port. It blasted the flour away. When moving from a stock plastic breech to a steel breech, Do I need to add anything to seal it better?
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TriggerHappy416
PostPosted: Fri Feb 21, 2014 10:55 pm 
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Are you missing the rubber seal that goes under the transfer port? (back rubber ring).

Upgrading to steel breech does not change the velocity.

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Digitaldawn
PostPosted: Fri Feb 21, 2014 11:00 pm 
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no I definitely have that in there. The transfer port I put it in the same style as this diagram says too. I made sure the larger side of the transfer port was facing upward as in the diagram

http://www.scopesandammo.com/parts/cros ... 77_pic.jpg
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blarg
PostPosted: Fri Feb 21, 2014 11:06 pm 
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See my last two suggestions....
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AirGunEric
PostPosted: Fri Feb 21, 2014 11:21 pm 
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If you haven't modded the piston or valve, and you cannot identify any leaks around the transfer port- take the hammer spring out and look it over- if you bent it up/crushed it as a result of the too long breech screw, it may be your issue.

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Digitaldawn
PostPosted: Fri Feb 21, 2014 11:47 pm 
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I checked the spring, its perfectly fine. I am definitely having trouble getting a nice seal at in the transfer port area. But according to the diagram the transfer port is properly in with seal. And the steel breech is screwed down completely.
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blarg
PostPosted: Sat Feb 22, 2014 12:08 am 
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If your gun is a rear cocker, pump and fire with bolt open to ensure good flow, there is restriction either in barrel port alignment, or bolt.
Pull breech and check that barrel port is aligned with breech port, and bolt port aligns with breech and barrel ports.
That's about all that's left if you have transfer port leaks.
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TriggerHappy416
PostPosted: Sat Feb 22, 2014 12:13 am 
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I have a feeling it might be your "chrony". Get a proper one or shoot into a phone book at point blank and count the pages so we have have some sort of tangible reference.

Btw, a bit of escaping air is always there at the transfer port since a perfect fit is hard to achieve. It is not significant enough to affect velocity much.

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Ace
PostPosted: Sat Feb 22, 2014 12:31 am 
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Where are you located ?

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