The barrel has two different ports, one for pellets and one for slugs. Check and see which one is being used. Is the transfer port on max/.25/.30?
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FX FX Crown mk2 .22 tuning, need help
- Thread starter pcpSWE
- Start date
Pellet port yes
transfer port on max. Check
What numbers should I excpect?
I hear 110bar and speed in the 900fps. Then I read some that are at 150bar and shooting 870fps.
Jsb 15.89 is what I was recomended and shooting in my gun. What fps should I aim for?
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Hi pcpSWE,
You are getting good advice from members here. For example, Greg (NAProf) knows Crowns - he owns multiple Crowns and has tuned them to very high accuracy.
I’ll step in and try to help…
In your pictures above, both adjusters are screwed out more than “factory”. I’d say screw it back in until just the dome (no threads) are showing. Then screw in 2 to 3 turns out - that’s about factory.
Set your reg back to 135-140 bar. That is the factory delivered setting for a FAC Crown .22.
Hammer spring adjuster wheel about mid-way (13).
Transfer port on medium. (Don’t need high for .22 - High may actually slightly decrease velocity).
If you can’t get 850+ FPS with these settings, then your Crown has an issue:
Your regulator pressure is not actually 135bar (gauge is way off - misreading)
Your hammer is not the correct weight (way lighter than it should be)
Your hammer spring is incorrect (not the proper spring)
As your velocity seems consistent, just low, I would not suspect a problem with the valve… at leastnot until I confirmed that the reg pressure, hammer weight and hammer spring are correct.
As others have already stated, a .22 Crown with the “factory“ settings I described above has no problem hitting 850+ FPS with 15.89/18.13 pellets - even with a short 380mm barrel.
-Ed
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Not so wild guesses (aka suggestions)
Hopefully this will not muddy the waters
Low velocity issues can often be caused by air leaks at either the transfer port or at the barrel O-ring
To check the transfer port, you can do the tissue test (search it on AGN)
I suggest doing the tissue test first as it is non-invasive
To check the barrel O-ring do so visually looking into the breech end of the barrel
This requires removing the barrel
Maybe there is another way I don't know about
But removing the barrel is pretty straight forward as there is no need to remove the shroud
Hope this helps
Edward
Hopefully this will not muddy the waters
Low velocity issues can often be caused by air leaks at either the transfer port or at the barrel O-ring
To check the transfer port, you can do the tissue test (search it on AGN)
I suggest doing the tissue test first as it is non-invasive
To check the barrel O-ring do so visually looking into the breech end of the barrel
This requires removing the barrel
Maybe there is another way I don't know about
But removing the barrel is pretty straight forward as there is no need to remove the shroud
Hope this helps
Edward
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You are following correctly. But you only increase the IHS if the velocity is steadily increasing. If it flattens out then you do not have enough reg pressure. You then increase the pressure (5 or so bar) and repeat. I personally do this a bit differently. I set the IHS to 4mm, then the reg pressure, then the Power Wheel to something like 10. I shoot and find velocity. If it is low, I increase the Power Wheel 2 clicks at a time until the velocity flattens out. If still not high enough I increase reg pressure and turn PW back to 10 and repeat. Once I get to a steady velocity 10-20 fps faster than I am looking for I use the IHS to fine tune down as long as my ES and SD stay low. Remember, each click on PW is 0.2mm of spring compression and each full rev of the IHS is 0.5mm of spring compression. So when I find the right spot, I adjust the IHS so I have anout 10 on PW.
Cheers,
Greg
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