Tuning Fx wildcat mk3 bt / fx maverick 27 gr slug tune

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bowopt

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Jun 14, 2020
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Centra java, Indonesia
Hello,

I have a 22 cal FX wildcat mk3 bt, and I'm trying to find the right tune for H&N HP slug 27 gr.

My gun setup is:

- 600 mm heavy liner
- 160 bar
- 11 gram weight plus a hammer weight addition, total about 12.4 gram.
- Huma tuning spring (stiffer than the FX)

With that setup and maxed the hammer at setting number 7 until I no longer can achieve more speed, I get about 1023 fps.

The grouping isn't great but not shotgunning. However, the gun is really violent, even when I lower the hammer to setting number 5 (about 990 fps).

Can anyone share their setting for wildcat mk3 bt or maverick for accurate shooting of HP slug 27 gr with 600 mm heavy liner?

Thank you.
 
Those are now the only slugs I really like using in my Maverick .22 :) The others are all erratic in my rifle, have good days and bad days, but the H&N 27gr are one holers every day of every week.

I get those speeds at 132 Bar, admittedly in a 700mm barrel.

Settings:

1st Reg 175 Bar (FX AMP MK 1)
2nd Reg 132 Bar (Huma MK3 X-Extra High Pressure)
13g Hammer Weight
PW 7
IHS CCW 0.75 - 1 turn
Pin probe at max length but does not interfere with magazine.

No difference in groups between Superior liner or Superior Heavy liner, use carbon liner on both.

Tuned BC at 995 - 1005 fps is at .131, which is way above manufacturers claim which is typically done at slower speeds I assume??

Rifle is relaxed and calm, big ass soup can silencer helps for sound level :)
 
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Hi Larry,

Thank you for sharing. It's detailed and I'm more encouraged to tuned it for the 27 gr now.

Can you explain to me why IHS CCW 0.75 - 1 turn means?

What would you reckon the 2nd reg should be at for 600 mm barrel? There's a video on YouTube that suggests using high reg pressure (that's why I set mine at 160 bar) to help with the harmonic, especially to control the valve to close faster.

Do you think that I should replace the Huma tuning spring to the original one to relax the gun and aim for about 1000 fps? Or to remove the additional hammer weight, instead?

I use fat boy 2 without the extension and it's loud compared to the hogan trident that I have. What silencer do you use?

Again, thank you.
 
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Your gun is shooting violently and loud as you’re blasting thru too much air. I bet your shot count is also not where you’d like it. From power wheel 7 to 5 you should also see more of a velocity drop than what you’re getting.

That hammer weight is giving an already longer spring more pre load which it doesn’t need. If you went back to the factory weight and hammer set up, you’ll get better results, and not be so violent on your shots as you put it.
 
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bowopt said:
Hi Larry,

Thank you for sharing. It's detailed and I'm more encouraged to tuned it for the 27 gr now.

Can you explain to me why IHS CCW 0.75 - 1 turn means?

What would you reckon the 2nd reg should be at for 600 mm barrel? There's a video on YouTube that suggests using high reg pressure (that's why I set mine at 160 bar) to help with the harmonic, especially to control the valve to close faster.

Do you think that I should replace the Huma tuning spring to the original one to relax the gun and aim for about 1000 fps? Or to remove the additional hammer weight, instead?

I use fat boy 2 without the extension and it's loud compared to the hogan trident that I have. What silencer do you use?

Again, thank you.
Click to expand...
Hi

The IHS is The Internal Hammer Spring(Adjust setting) on Maverick power wheel. Turn it CCW from all in to where you get desired speed. Mine is at about 0.75 to 1 CCW of a turn out.

Start Reg pressure at 125 bar and work up from there, probably will need +-135 bar with 1 - 2 CCW turns on IHS and using power wheel setting 7??

I have DonnyFL Ronin on mine :)
 
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