FX Crown mk2 - regulator pressure changes after each shot

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merpo

merpo

Member
Apr 17, 2022
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Bratislava, Slovakia
Hey,

I tried to lower the reg pressure on my Crown from the factory 100 to around 60, possible a bit lower.
I followed the manual and gently turned the reg screw 1/4 of a turn, shot until it stopped getting lower on pressure.

After I got to the wanted figure I started chrono it but I saw big difference between each shot in FPS. Eg 850 then 760 etc..
Looking at the reg gauge I see that after each and every shot it changes its pressure from e.g. 50 shot 60 shot 50 shot 60…
I tried to increase the pressure to 100 again but it keeps doing the same. 100 shot 110 shot 100 shot 110…

Any idea what’s going on and how to fix it?

Thanks!
 
Try like douger said. Degas and empty the plenum. Then screw in the reg till it stops moving. Put the bottle back on, and start turning the screw till you reach desired pressure. Then test fire a few shots and see if it stabilizes. Even though the amp regs can be lowered while pressurized, it takes some time for them to settle in going down. If you’re going up in pressure, then tend to settle quicker.
 
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I'm not sure why you would want to run your reg pressure that low, and I'm not sure but I think I read where FX has a recommended minimum set pressure for the AMP regulator. 60 bar is only 870 PSI... seems really low. I have my Crown reg set at 110 bar and by adjusting nothing but the hammer spring I can dial in anywhere from 10 to 22 ft.lbs. of energy.
Anyway, when my Crown started showing erratic reg pressure from shot to shot and significant reg creep the problem was a bad O ring on the reg adjusting screw. I replace both of the O rings on the reg adjusting screw and the problem was fixed. It was easy. I have attached the schematic for your rifle below, the O rings I replaced are item #D32. They take a little patience to change out because they are so small and stiff. Soak them in some hot water to soften them up before trying to install them.
I would suggest you call FX USA in North Carolina (866-639-0772) and talk to one of the techs, they are VERY good and will get you pointed in the right direction. You can also ask them about the minimum suggested reg pressure setting for your gun. Have your gun serial number handy and if it is still under warranty they will be happy to send you the O rings for free. They are super nice people and extremely helpful.
Good luck... Chip.
https://fxairguns.com/wp-content/uploads/2020/02/Crown-200204.pdf
 
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cwcarrera said:
I'm not sure why you would want to run your reg pressure that low, and I'm not sure but I think I read where FX has a recommended minimum set pressure for the AMP regulator. 60 bar is only 870 PSI... seems really low. I have my Crown reg set at 110 bar and by adjusting nothing but the hammer spring I can dial in anywhere from 10 to 22 ft.lbs. of energy.
Anyway, when my Crown started showing erratic reg pressure from shot to shot and significant reg creep the problem was a bad O ring on the reg adjusting screw. I replace both of the O rings on the reg adjusting screw and the problem was fixed. It was easy. I have attached the schematic for your rifle below, the O rings I replaced are item #D32. They take a little patience to change out because they are so small and stiff. Soak them in some hot water to soften them up before trying to install them.
I would suggest you call FX USA in North Carolina (866-639-0772) and talk to one of the techs, they are VERY good and will get you pointed in the right direction. You can also ask them about the minimum suggested reg pressure setting for your gun. Have your gun serial number handy and if it is still under warranty they will be happy to send you the O rings for free. They are super nice people and extremely helpful.
Good luck... Chip.
https://fxairguns.com/wp-content/uploads/2020/02/Crown-200204.pdf
Click to expand...
New into this. I was thinking, lowe reg pressure = higher shot count.

Anyway, I set it to 110bar, it seems to feel just right at that pressure and it’s rock stable now.
Tuning it into FT gun, <12fpe, .177 cal.
Now I’m getting nice 798 fps with 8.44gr JSB.
 
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That is exactly what I use my Crown for except I am shooting just shy of 20 FPE with 10.3's in hunter class. The gun shoots amazingly well (me not so much). My reg is set at 110 bar and I am getting so many shots per fill that I have never wanted to waste that many pellets to find out the number! Enjoy your Crown, I love mine! Chip.
 
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