Tuning Improving Maverick Shot Consistency

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marl3y

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Apr 26, 2021
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WI, United States
I've been trying to improve the shot consistency out of my FX Maverick. I polished the hammer, hammer weight, hammer spring and trigger sear. This is a .22 with 700mm barrel, using the pellet probe and port. The first reg is 140 bar and second is 110 bar. Here are two shot strings with JSB 18.1 gr (power wheel=4) and Crosman 14.3 gr (power wheel=2) pellets. Minimum 10 seconds recovery between shots. I feel like things could be tighter, but maybe not. Any suggestions? Thanks.

JSB 18.1 gr - 870 898 901 869 898 880 865 875 887 877 873 852 866 893 890 876 860 863 848 869 891 872 861 876 885





Crosman 14.3 gr - 841 827 857 843 851 834 840 847 832 826 835 844 851 850 865 823 821 822 858 845


 
That spread does seem excessive. What are your spreads at different power wheel settings? I just switched over my 700mm from .30 to .22 and had to decrease the adjustment to get consistent shot strings. 
I ask about the power wheel settings because with a minor adjustment the string tightened up for an extreme spread of 9 versus the 27 I started with. Just trying to give some different ideas but you may have already done this. 
 
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Many thanks for the insightful responses. A few other details on the setup. The HS preload screw is most of the way out, so high pre-load. Basically I set it so with JSB 25.4 gr were a bit over 900 FPS and then turned it down to around 900 FPS. That's the max power I need for those pellets or slugs of that or slightly less weight. Maybe it's just silly to try for a reg pressure/HS pre-load to handle ammo from 14.3 to 25.4 gr. 

I haven't generated shot strings at multiple PW settlings, but have focused on the setting that's closest to the target of 840-880 FPS.

I wonder of the 2nd reg is actually too high. I rarely shoot the heavier ammo, so maybe I should focus on the 18.1 gr JSBs and balance the 2nd reg and HS pre-load. Maybe go down to 90 bar on the 2nd reg and 120 on the 1st, then find the HS pre-load that's around 900 FPS for 18.1 gr pellets at PW=7 (assuming that can be reached).

Thanks, really appreciate the feedback from this forum. 
 
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Many thanks for the insightful responses. A few other details on the setup. The HS preload screw is most of the way out, so high pre-load. Basically I set it so with JSB 25.4 gr were a bit over 900 FPS and then turned it down to around 900 FPS. That's the max power I need for those pellets or slugs of that or slightly less weight. Maybe it's just silly to try for a reg pressure/HS pre-load to handle ammo from 14.3 to 25.4 gr. 

I haven't generated shot strings at multiple PW settlings, but have focused on the setting that's closest to the target of 840-880 FPS.

I wonder of the 2nd reg is actually too high. I rarely shoot the heavier ammo, so maybe I should focus on the 18.1 gr JSBs and balance the 2nd reg and HS pre-load. Maybe go down to 90 bar on the 2nd reg and 120 on the 1st, then find the HS pre-load that's around 900 FPS for 18.1 gr pellets at PW=7 (assuming that can be reached).

Thanks, really appreciate the feedback from this forum.
Click to expand...

If I were going to shoot 14.3 grains I would turn the regs down to stock level at 125/100. My Sniper came from Utah Airguns set at 125/100 and the Compact came from Pyramyd Air set at 150/100, which I think came from the factory. I would be very interested to hear how the 120/90 turns out. 
 
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Yep, I went the other way, but maybe that's the wrong logic. I'm at lower reg pressures. Seems like there are different schools of thought, but I haven't seen compelling data one way or another. Here's what I'm seeing with the 18.1 gr JSBs, albeit small numbers at each setting. Happy to try other combos and post back. Thanks.

Screen Shot 2021-10-05 at 9.16.30 PM.1633486600.png

 
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I've ended up at a similar tune, with 2nd reg between 90-95 bar for my Maverick Sniper .22. I used the HS adjustment to set power wheel setting #2 at about where you have your #7, with speed at about 940 fps and a decent ES of 9 fps. That way, I can turn up the HS for shooting hybrid slugs or other lightweight slugs. My Maverick with the Superior barrel does not seem picky about the tune when shooting JSB 18.1s. I've gotten great accuracy from 30-100 yards using several different reg+HS combinations; however, it is nicer to shoot with lower reg and HS and uses less air. 

I have to say that I have really enjoyed the Maverick. Having externally adjustable reg pressure and HS has let me experiment and learn so much more about shooting a pcp than was possible with other guns that I have.
 
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Appreciate the follow up. I can try increasing the HS pre-load tension too. My logic was keeping it lower to get more useable range out to the power wheel. At some point the velocity. curve really levels off. It seems that either approach, low or high reg pressure can produce low ES. I guess I just need to keep fiddling and measure the results. Thanks.



Edit: Would you mind posting some representative speeds at other power wheel settings? Just curious. Thanks.
 
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OK, I bumped up the HS pre-tension two full turns. Here are graphs of 18.1 and 14.3 gr pellets, as well as a 10-shot string at about where I'd shoot them. Actually too fast for the 14.3 gr, but you get the idea. A couple of additional observations, the 2nd reg only opens after every shot at power wheel setting 3 and higher. So at 1 and 2 the pressure in the plenum is probably more variable. Also, 95 bar on the second reg can only be achieved by barely cracking that reg open, meaning it can't go any lower. Assume that's normal, but wanted to share. Things tighten up at the higher power wheel settings, but that's too fast. So, I'm not sure how to reduce FPS from here and keep ES low. I guess an alternative may be cranking up the pressure on both regs and reducing HS. Part of me feels like that might be better for the 2nd reg since now it's nearly closed.

Screen Shot 2021-10-06 at 7.38.52 PM.1633567496.png

 
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I run 130/95. 6ES. 2.2 SD 25 cal. 914 wheel 6 This is where accuracy kicks in. 100 yds, 1 mag shoots center out of 8" splatter burst target. 

I had you're problem when I first got mine and tried improve perfection. 

I feel you're regs are too high. Probably 120/90 would get you to 900 on wheel 4 or 5

I try not to be at the top or bottom of any adjustment.

Just my .02 worth. Every gun is different!
 
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Ah yes, mines a compact. With 700 you jump way up on fps. Set wheel on 7 and lower reg until you're at 920 some say higher. Run a chrony for each wheel setting. Check accuracy. You'll get there.. Some will argue but this is part of the tuning process. Higher speeds and hammer will allow a tune UP for slugs and heavier 22. Works for me.
 
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Thanks, this is similar to my typical approach... For a given reg setting and target max FPS (plus about 20) for the heaviest intended ammo. Then set power wheel on max and turn up hammer spring until there's no significance increase in FPS. If the target speed isn't reached, increase reg pressure and repeat. Once you hit the target velocity +20, turn down the HS a bit to the true target. Possibly the problem with this is if it's done with 25.4 gr pellets to shoot 18.1 gr accurately the power wheel needs to be lowered, resulting in an increase of ES for that ammo. I can try the above focusing on 18.1 gr and see what happens. Unfortunately based on 18.1 gr my graph above I'm already over my target speed, so maybe just reducing HS will do it. Appreciate the responses. 
 
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Many thanks for the insightful responses. A few other details on the setup. The HS preload screw is most of the way out, so high pre-load. Basically I set it so with JSB 25.4 gr were a bit over 900 FPS and then turned it down to around 900 FPS. That's the max power I need for those pellets or slugs of that or slightly less weight. Maybe it's just silly to try for a reg pressure/HS pre-load to handle ammo from 14.3 to 25.4 gr. 

I haven't generated shot strings at multiple PW settlings, but have focused on the setting that's closest to the target of 840-880 FPS.

I wonder of the 2nd reg is actually too high. I rarely shoot the heavier ammo, so maybe I should focus on the 18.1 gr JSBs and balance the 2nd reg and HS pre-load. Maybe go down to 90 bar on the 2nd reg and 120 on the 1st, then find the HS pre-load that's around 900 FPS for 18.1 gr pellets at PW=7 (assuming that can be reached).

Thanks, really appreciate the feedback from this forum.
Click to expand...

I noticed that here you said that you had high preload. When I have my 2nd reg down around 90 bar, I don't have hardly any preload on the HS. Otherwise, velocity is already maxed at the lower settings on the adjuster. With the 700 mm barrel, it doesn't take much pressure to push those 18.1s. BTW, I never really know what pressures I was running until I replaced the stock gauges with Wika gauges.
 
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