Tuning Maverick Power Wheel Works In Reverse?

This means you have way too much hammer spring adjustment, turn done your HS adjustment screw until it goes back to normal. 

Sorry to correct you qball but its because you’re using more pressure than you’re hammer can overcome. Get a 30 cal hammer or a slug power kit ( which comes with a 30 cal hammer and a 22-25 pin probe) and you’ll be right as rain

while im here while tuning use very small air and spring adjustments. The maverick doesn’t give best results to big jumps

If the Hammer is too little then the HS adjustment won’t work in reverse, speed would just plateau. I had the hammer too light problem before. OP maxed out HS right off the bat which isn’t always the best tune. 


The .25 version should come with medium weight or 11 gram hammer which should sufficient for 155 bars, upper end of it but should still work. 

Too much hammer spring or not enough reg pressure you can look at it either way.

Most likely when you were at 155bar it was 5 too much. I had the same thing happen with my 22 which is why my 1st answer is what it is. I haven’t been able to figure out what it is. Also with my 177 compact i cant go over 80 bar without things going weird and to the best of my knowledge every thing inside should be the same as my 22sniper so i would think i should be able to at least 112 bar but no way

The 13 gram hammer is the heavy hammer and can push regulator pressure up to the max rated 170 bars. if you want more power then you can add 5-10 bars to the second regulator. If you want the power wheel to work like it should then reduce the HS screw a couple of turns. 

When I had a similar puzzle, the experts here explained to me that when there is too much hammer it hits the valve rod so hard that it rebounds, closing faster than it would under just the effect of pressure and valve spring, giving you LESS velocity. As you reduce hammer the rebound decreases and velocity rises as the valve stays open longer. Eventually you will decrease hammer enough that there is no more rebound, after which decreasing hammer reduces velocity. From your description it does sound like too much hammer for the reg pressure.

Qball, when u say max rated 170 bar on the first regulator, is that the maximum differential pressure it can be set for? Give me some examples, thks.

I just wanted to say yesterday I decided to adjust my hammer screw to gain the normal function of the power wheel. I had gone under the assumption that with the heavier hammer weight and to get it to work with a higher regulator setting of 150 bar that I would need to adjust the screw out to the maximum length of 6.00 mm. I started by taking out the hammer adjustment screw and holder and screwed the adjustment screw all the way in to it bottomed out. I like the way Airbuks takes his measurement by measuring the holder and screw together and then subtract the holders width. I think that works better than using the end of the caliper tail to take the measurement. Of course where ever you get the results needed it is what it is and then you tighten the set screw. With adjustment screw bottomed out it only stands out at 1.98 mm. I started with the second regulator at 145 bar and turned out the screw starting at about a quarter turn at a time which only moves it out about 0.10 mm. In the end to get 956 fps with the NSA 49.5 on power wheel #7 the screw only had to be out at 2.60 mm. That gave me normal function of the power wheel with a fps increase from #1 to #7. I guess in the end with the heavier hammer weight not that much pre-load is needed. I hope this info helps other that have this problem and thanks to those that gave me insight into my problem. Bill

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That's the way to go! I think the worst bit of information that has gotten around is the "set the adjust screw to 6mm". Somehow it went from that is your max, to set it to that, lol. I'm not blaming anyone, I just think the word got out and eventually morphed into set it at max. Almost no one will need to to set it at 6mm. Even on my "hotrodded" maverick, I think mine is around 3.5-4mm. Sure, I can see instances where the entire 6mm could be used, but the cases where it would be needed are very few. Sounds like you've got that bad boy doing what it should be doing now

Guys, I've been trying to get my maverick sniper .30 to put nsa 49.5 slugs out at best velocity and I'm lucky to even get 910 fps. It honestly seems like FX put the wrong hammer spring in my maverick. So I took out the hammer spring and measured its length. It is 52mm long. Do you guys happen to know how long the hammer spring is in your maverick sniper 30 cal?

Guys, I've been trying to get my maverick sniper .30 to put nsa 49.5 slugs out at best velocity and I'm lucky to even get 910 fps. It honestly seems like FX put the wrong hammer spring in my maverick. So I took out the hammer spring and measured its length. It is 52mm long. Do you guys happen to know how long the hammer spring is in your maverick sniper 30 cal?

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You need to get the heavier hammer weight to open the valve up at the higher regulator pressures you will need to use. Then gradual work up your hammer spring and regulator adjustments as I did above. I by the way bought the Huma-Air power kit to get the heavier hammer weight. Bill

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Thanks Bill. I have the heavy hammer weight (13 gram) and a huma hi-flow pin probe. My hammer SPRING is 52mm long and I think FX put the wrong spring in it, but I can't be sure unless I verify with someone that has measured theirs. That's why I asked if anyone happened to know the length of the spring they have in their maverick sniper .30. I guess I'll just order a replacement spring and hope it's different and better rather than the same one I have now.

Guys, I've been trying to get my maverick sniper .30 to put nsa 49.5 slugs out at best velocity and I'm lucky to even get 910 fps. It honestly seems like FX put the wrong hammer spring in my maverick. So I took out the hammer spring and measured its length. It is 52mm long. Do you guys happen to know how long the hammer spring is in your maverick sniper 30 cal?

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You need to get the heavier hammer weight to open the valve up at the higher regulator pressures you will need to use. Then gradual work up your hammer spring and regulator adjustments as I did above. I by the way bought the Huma-Air power kit to get the heavier hammer weight. Bill

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Thanks Bill. I have the heavy hammer weight (13 gram) and a huma hi-flow pin probe. My hammer SPRING is 52mm long and I think FX put the wrong spring in it, but I can't be sure unless I verify with someone that has measured theirs. That's why I asked if anyone happened to know the length of the spring they have in their maverick sniper .30. I guess I'll just order a replacement spring and hope it's different and better rather than the same one I have now.

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The factory spring in my Maverick is 56mm long, fwiw. I actually don't even have it in my gun, because I'm using the Huma Impact hammer spring. I say go ahead and order a spring(or the Huma spring). The Huma spring is actually slightly shorter, but a little stiffer. Do you have the spacer on the hammer weight or is it just the spring and weight? More spacers may be worth trying too.

Rallyshark, thanks for that info. I've read a lot of your posts about .30 maverick sniper -- sounds like yours is working great. My maverick sniper .30 was ordered that way -- in other words I didn't get a .22 or .25 and then swap anything to get to .30. Mine came with the 13 gram hammer weight and the 52mm spring and no spacers (I assume they are just plain flat washers I could get at any hardware store -- maybe smooth them with sand paper before using in the maverick). That's probably more info than you wanted to hear, but more detail is better I think. So I am told that my barrel liner has a 1:22 twist rate which should be good to stabilize slugs up to 50 grain. I really like nsa slugs and want to get the 49.5 slugs to go bad-ass fast and then back off as needed to get accuracy. So I proceeded to do exactly what Bill did. Went through about 200 slugs and took notes on every shot (about 6 pages of double-column notes on letter sized paper -- took all weekend). The pattern clearly showed it's ugly head. The best velocities I could get at air pressures from 120 to 155 bar (creaping up by about 3 bar at a time and starting with the hammer wheel on 7, but cranking in the hammer screw all the way and backing the screw out 1/4 turn at a time for each shot at each air pressure until it was too far out to cock the rifle). The best velocities I got at every air pressure was when the hammer spring was fully preloaded. Absolute best I got was 915 fps at 130 bar. I replaced o-rings around breach area thinking I might have a leak, but no change and no leak. Barrel is very clean (I silicone lube my nsa slugs even though nsa lubes them before shipping and I always get rid of the excess oil, so I'm not over-oiling).

So it just seems pretty obvious that my maverick wants that heavy hammer to smack harder. The bottom line is that I will get a 56mm spring and have another go at it and I think those 49.5 nsa slugs will really scream. I won't use spacers with the longer spring. Sorry for rambling so much -- I'm just kind of excited that someone actually verified that a 56mm spring came stock in their maverick -- exactly what my maverick seems to want.

Thanks Rallyshark. +1 accuracy to you.

Edit: It just occured to me that I should point out that both of the air gauges on my maverick are WIKA 0-250 bar gauges. It came with a WIKA for the air tank, but had the el-cheapo toy gauge on the rear. I replaced the toy gauge with a WIKA before trying to do any tuning.

Just another fyi, but I would order that spacer from FX, if you order the spring from them. I don't think it is a "normal" sized spacer you could just grab at the hardware store. It probably wouldn't be a bad idea to have one on hand, just in case I am using the spacer on mine, and I was using it prior to putting the Huma spring in it too. Granted, I'm pushing my gun harder than many do, but I've always used that spacer on pretty much every tune. Good luck, I hope the new spring gets ya sorted out! 

A lot of misinformation has been put out about the Maverick, Starting with the poor owners manual. Then came the vague, incomplete and even wrong information on fx you tube. Not until Matt came out with HIS IN DEPTH regulator adjustment did I fully understand the adjustment procedure.

Now I've been enlightened by you wonderful guys about the hammer screw! I followed the ( apparently wrong) 6mm instructions. I've have similar problem where 6&7 settings give me no more or less fps. The conundrum is that I have a very good shooting gun on 1-5. 6/2.2. On 2 I get 4/1.8. However I can not achieve slug speeds. I did previously. Until I 6mm'd the hammer. I didn't catch on till these posts. When you have a spot on shooter ( 25g) it's hard to understand your set up wrong.

I have 25 compact, believe it or not, I 8" gong it @ 155 yds. But not enough fps for 34g or to tighten the spread. Like to put a longer barrel on but you can't get them.

Thanks every body. Now I have something to go on!