Desperately need help. FX Crown tuning

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Bramezy

Bramezy

Member
Jan 1, 2018
716
435
Hamilton, Ohio, United States
Hey all.
Please read and not assume.
Hope im missing something but im about done with my first FX. Its a 22 600mm. Im trying to shoot 16/18gr pellets.
So when i received this thing a few months ago i first threw some 16gr pellets in and shot over my fx chrony. Im not worried about the discrepancy in the accuracy of the fx so please dont blame that, i need real input.
It was shooting 915 to 860. That was my spread. I had asked for a tune and thats what i got. Thats not why i bought an FX, for a 50fps spread.
So i started looking into how to tune. That 50fps spread grew to 100fps. I tried the AEAC tune, i tried someone elses starting point of reg pressure down at 80 and work up from there. Ive tried others working tunes and im so far off. The closest ive gotten to any consistency is at 90psi and almost max hammer spring and medium setting and im at 820. Its actually consistent 819-821. Thats great but thats not fast enough for 100yd benchrest or PRS shooting. With hammer spring on max its 830-844. As i increase reg pressure the fos goes down no matter what i try. I just put in the new brass AMP reg and its no different than the stock AMP reg. Ive gone as high as 120psi and my fps goes down to 715 and lower.

I really wanted a nice highend accurate smooth gun and finally settled on the FX Crown. Im about done with this and FX.

Can anyone help, like really help? Ive heard all the stupid comments and please dont waste my time of haters.

Im looking for guidance. Ive taken the gauges off, valve out, hammer and soring out and bottle off and everything looks clean so nothing obvious sticks out to me.
Ideas?
Thanks for your time.
 
I have 2 FX Crown MKII"s. One is in 22cal. I have the reg set at 150 right now and have no problem shooting 16/18's or even 25's at 915 fps. The key with the Crown is the higher the reg pressure you go, you will also have to take the stock off and increase the Internal hammer spring to match the reg pressure. For example, if you went to 120 bar and it went down to 715, that is an indicator that your internal hammer spring is too low.
If your wanting to shoot 100 yard bench rest, then you need to be at 150. The Crowns don't seem to like the lower pressure as much as some other FX guns do.
If you have any more question and don't want to put them on here, you can PM me as well as I have the same airgun except with a 500 mm barrel in 22cal.
 
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I had a similar issue with my first crown. Turned out the hammer spring was broken, and causing my spread. It’s not an isolated case also. There have been many crown owners with similar issues caused by a broken spring. Mine was broken straight out of the box. Others have been also.
I would take it apart, and pull the spring. See if it’s indeed broken. The crown is one of the easiest rifles to tune well. Once my spring was replaced, I was shooting monster redesigns at 950fps with a sd of 2.4. That’s the kind of consistency you can expect from your crown when working properly.
 
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Just a quick question that you didn't mention in your post. During your tuning are you also adjusting the internal hammer pre-load screw? It's the one that you have to remove the stock to get to. You sound frustrated but please don't give up. Is this a MK2 Crown. The Crown MK2 is a really terrific rifle and everyone really seems to love them. I actually have two and they are my favorites out of many pcp rifles. If you are not utilizing that internal hammer pre-load then that will most likely be the source of your tuning problem.
Kenny
 
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here are the spring next to each other. Broken on the left.
6F524585-039B-4F91-B13B-CAC82BB95FA4.jpeg
 
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Kgphotos said:
Just a quick question that you didn't mention in your post. During your tuning are you also adjusting the internal hammer pre-load screw? It's the one that you have to remove the stock to get to. You sound frustrated but please don't give up. Is this a MK2 Crown. The Crown MK2 is a really terrific rifle and everyone really seems to love them. I actually have two and they are my favorites out of many pcp rifles. If you are not utilizing that internal hammer pre-load then that will most likely be the source of your tuning problem.
Kenny
Click to expand...
Was my problem! Was very loose.
 
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saitama said:
In my case, the factory hammer was too weak and needed to be made stronger by screwing it on tighter.
Next I set the regulator pressure from 135bar to 140bar.
I am now shooting 18gr pellets at 905fps.
Click to expand...
Im down at about 112-115bar shooting 18gr 875. was over 900 at 120 bar.
 
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madeintheuk said:
here are the spring next to each other. Broken on the left. View attachment 334346
Click to expand...
wow, just that tiny bit broken. i know mine is good, i had it out and cleaned up the edges on it. I wanted to check for things like this in case it was something obvious. Im learning FX and in my tearing down, i like the simplicity compared to the Impact and such. I wanted simple.
 
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