Correct balance Reg pressure, TP hole, HST RAW HM1000X conversion .25 to .22

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mubhaur

mubhaur

Member
Nov 8, 2015
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Karachi, Pakistan
Dear Members
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,

I hope you will be fine.

You might know that I had imported two HM1000X in .25 60 ftlb from RAW Martin.

Later I decided to convert one of these fine guns into .22 in order to shoot 18 grain and 25.39 grain redesigned monsters.

I installed a .22 barrel with index-able TP. Pics attached.

At all previous settings i.e. for 60 ftlb, my gun now shot 25.39 grain at 935 fps and 18 grain at 1050 fps.

But the gun barks now. I understand that the gun is wasting air.

I unscrew the HST complete 3 turns and during this the fps went up and then came down to the same 1050 fps with 18 grain.

But the gun still barks.

I understand that if I reduce the size of TP, the matter may be resolved and at the same fps I might get more shots and less noise.

Please advise me about the complete settings to achieve 950 fps with 18 grain and 950 fps with 25.39 grains.

Regards,

Umair Bhaur
 
Hi Umair,

Since you have a .25 caliber rifle as well, shooting 60 fpe, I would pull the barrel on that gun and compare the transfer port size against the one you put into the thimble on the .22 cal. My guess would be to start with the same size TP as on the .25 cal for the .22 cal and maybe go a little smaller to start with (allowing you to slowly open up the TP size if needed). You may end up needing to experiment to find the right size TP for that caliber.



Anyway, that is how I would approach sizing the TP. If someone here has a .22 cal shooting in the 950's perhaps they can pull their barrel and get you a measurement. That would probably only be a starting point though and may be different due to having the thimble on your gun.



Sean
 
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If the gun is still wasting air you are striking the valve too hard (or too long) Try a lighter spring.
Click to expand...

So should I reduce the regulator pressure? I think decreasing regulator pressure will open the valve much more and more wastage of air.

On the other hand I feel that if I reduce regulator pressure and also reduce hammer Weight and hammer spring, then I might be able to save air and reduce the bark.
 
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