Tuning FX Maverick / Wildcat MK III heavy hammer adjustment

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tefloncoated

tefloncoated

Member
Oct 15, 2015
187
56
PA/NY, United States
Hi gents

Like some other folks, my .25 Maverick Sniper came with the lightest hammer from the factory for some reason.

In that configuration, it shoots JSB Heavies MK2s at ~890 fps with working reg set at 105 bar, hammer adjustment screw at 6mm and hammer spring adjustment wheel on 7. 

This is max working pressure/speed for that hammer - it can't punch through anything higher than 110 bar, speeds start to drop at that pressure.

I just installed the heavy (.30 cal) hammer weight from FX, bumped the working reg to 135 bar, hammer adjustment screw still at 6mm and am having an odd issue: max speed with same pellet is now 875 fps. I don't know what's going on... but what seems even more weird to me is that 875 fps comes on "Adjust", not on #7 power wheel setting. On #7 actually get the lowest speed, 765 iirc...this is frustrating.

Any ideas what I should look at to get the speeds up? Thanks in advance.


 
teflon, this is odd, and we can solve this. I have some questions to ask allowing me to understand the differences between our two Mavericks.

  • Who did you buy the FX from?
  • What is your hammer weight?
  • What grub screw adjustment "type" is your 1.5mm? (photo) There are two types I have seen.

Mine is the G1 Maverick from the first shipment from November 2020 in .22, I also have a G1 WC MK3 in .30 that essentially is the same air rifle sans the extra reg. My hammers are 7g for the .22 and 13g for the .30




 
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  • Who did you buy the FX from?
  • What is your hammer weight?
  • What grub screw adjustment "type" is your 1.5mm? (photo) There are two types I have seen
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Thank you!! 

It came from SPAW, who has been completely unreachable for help, unfortunately. I had to go directly to FX USA who have been very helpful. They sent me the right part - a .25 hammer weight and I also purchased the .30 weight as well. The adjustment screw is 2.8 mm, set at 6mm out. Here's a pic, with original weight I the center.

IMG_20210328_092935.1616938778.jpg







 
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Now I see, sorry didn't read your post completely.

B
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No worries! Oddly, I think tightening the adjustment screw all the way in seems to help. At 125 bar on the working reg, I'm able to push the MK2 JSB heavies at 950 fps. What's funny is that the adjustment wheel is no longer an indicator of power - I get higher speeds on 3, 4 and 5, with lowest at 6 and 7. I saw in Krale video of the power kit exactly that as well: https://youtu.be/lERTBEbbAyE?t=664




 
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FX has 3 hammer weights, 7.3g, 11g and 13g. As you already found out 7g version is for regulator pressure up to 110 bars and heavy is for 150-170. Having a heavy hammer doesn’t always mean you get more power as it is hitting the valve too hard. You are exhibiting very normal behavior of way too much HS. My suggestion is to order the medium or 11g hammer or dial up the reg pressure to 150-160. Even you get the medium hammer you most likely will still need to turn down the preload.

 
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FX has 3 hammer weights, 7.3g, 11g and 13g. As you already found out 7g version is for regulator pressure up to 110 bars and heavy is for 150-170. Having a heavy hammer doesn’t always mean you get more power as it is hitting the valve too hard. You are exhibiting very normal behavior of way too much HS. My suggestion is to order the medium or 11g hammer or dial up the reg pressure to 150-160. Even you get the medium hammer you most likely will still need to turn down the preload.
Click to expand...

That's great info, thank you. Luckily, I already have all three weights and can play with these combinations in the next few days. Thanks again!
 
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Click to expand...

That's great info, thank you. Luckily, I already have all three weights and can play with these combinations in the next few days. Thanks again!
Click to expand...



Here is a great video for tuning airgun for max power, even through it's an impact but the approach is the same. 

https://www.youtube.com/watch?v=vaeGVbasD7Q

Quick summery of the video: Put your HS power wheel to 3 or middle and see what your speed is. If the next higher setting gains 20-30 FPS then add or reduce HS preload until the next setting only gains under 10FPS. This is the max speed for your Reg and HS combo and most efficient and accurate power setting is the one lower which loses around 20FPS. Every time you change regulator pressure you need to repeat this process. 

Example: HS 3 = 900FPS, HS 4 = 925FPS and HS 5 = 930FPS

HS 4 would be your highest power sweet spot but HS 3 will be your true sweet spot with best efficiency, accuracy and noise. Once you found your sweet spot you can adjust your preload so that Max or 5 will be your sweet spot at 900 FPS and then you will have many lower power options that are all very efficient. You should not hear the PPPSSSSSTTTT noise like when you are shooting at 930FPS in the example.







Given you have a sniper or 700mm version you max sweet spot speed could be around 940-960FPS range if you crank the gun for max power. At 135 bars you probably will shoot the 34 grain slugs at around 920-930 sweet spot. The maverick has some serious power but JSB heavies are best right at 830-860. 






 
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Playing with my Maverick ( .177 ) i ha having problems getting to the higher speeds with heavy pellets like the MRD and beasts, with the reg set to 140 BAR and the hammer adjustment screw backed out so far you can barely load the rifle, my speeds top out at 900 FPS for the MRD pellets and as i recall barely 800 FPS for the Beasts.

But i get the same speeds with the reg set to 125 BAR ( same hammer setting ( 7 ) and adjustment screw all the way out.

And i can actually turn the adjustment screw 1-2 full revolutions before speeds start to drop.
 
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