Question for those who shoot the 34gr pellets from the FX Maverick in 25 caliber, even better if it's the 600mm barrel. I'm curious what velocity and tune that you use? I've been playing around with the tune on mine with the 600mm barrel and 11gr hammer weight. Right now my regs are 160/140, not sure exactly where the IHS is at, somewhere in the middle, and I'm getting 940fps on PW7. My goal is to have them in the 950fps range since I don't shoot very far and want the extra knock down power. I'm still trying to dial in the tune to get my velocity spread down.
FX Maverick 25 caliber 34gr pellet tune question
- Thread starter TheCarFather
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Here's a shot string from mine. Not sure on regs as I had my local guy tune for me. He was shooting for AEAC pro tune and as I recall the ave speed was right on the money. Oh, I see the reg settings at top of this chart.
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I have the 25 cal, 600 mm barrel. Shooting 35 grain pellets at 888. 1st reg 145, 2nd reg 118, hammer wheel at 6.
When I was playing around with it adding 5 bar to the 2nd reg got me about 10 fps increases. I'd increase your second reg a little at the time until you reached your goal and then increase the first reg a bit to improve the filling of your plenum between shots.
When I was playing around with it adding 5 bar to the 2nd reg got me about 10 fps increases. I'd increase your second reg a little at the time until you reached your goal and then increase the first reg a bit to improve the filling of your plenum between shots.
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The trouble I'm running into when tuning is if I try the popular method of setting the IHS all the way out to max, and starting with a low reg pressure and working my way up, that at lower reg pressure the hammer overpowers the valve so the velocity is lower than it "should" be. Example, if my reg is at 110 with IHS maxed, the velocity is in the 700's. If I start turning the IHS in, velocity goes up. I understand how that works, it just makes tuning tricky.
So I'm just looking for potential tune ideas from others with a similar setup. FWIW my Maverick is shooting very well as it sits, but I'm always looking to improve. It's all part of the fun for me.
So I'm just looking for potential tune ideas from others with a similar setup. FWIW my Maverick is shooting very well as it sits, but I'm always looking to improve. It's all part of the fun for me.
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Another quick question, is it common to experience higher velocity spreads on lower power wheel settings? On my Maverick, both when it was previously 22 caliber and now 25 caliber, I always get the tightest velocity spread on PW7/6. As I drop below 6 my spread increases. I'm still pretty new to all of this so I'm learning as I go, thanks to this place and the search bar I've learned A TON!
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Mine is a tiny bit more consistent at 6 vs 7. And the fps only dropped 3 fps going down to 6. And it's 5-6 dB's quieter at 6.
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I've found that you absolutely need to have the Hammer Micro (FX's term) at a known number, I use 20.34mm, FX says 19.3, that takes a dial caliper. Also make sure the bolt is snug so the adjustor won't shift accidently.
Maverick. VP 600
HSA Hammer Micro 20.34
Hammer Macro # 5
120# Front
78#. Rear
937 fps about 2.0 sd
JSB Match Diabolo Exact King .25 Cal, 25.39 Gr
Maverick. VP 600
HSA Hammer Micro 20.34
Hammer Macro # 5
120# Front
78#. Rear
937 fps about 2.0 sd
JSB Match Diabolo Exact King .25 Cal, 25.39 Gr
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Usually accuracy for them is some where between 850 to about 930 I would try a little higher second reg set up to try and keep from overpowering the valve and having it bounce back shut right away it would be harder to do being Maverick doesn't have the valve control knob like the impact does which also seems to help control spread some I think it will take some playing around with the second reg more to find the right setting
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I'll be doing some more chrono testing this weekend, but after my adjustments made yesterday the gun is shooting fantastic, I can hear it's much quieter now. I hadn't verified the front reg pressure since getting the gun back from FX, where they stated the reg was set at 160. Last night I wanted to bump the front reg a little and found the front reg set at 185. My rear is set at 140, so I lowered the front reg down to 170. We'll see if that will help tighten up my spread on PW5. Like I already mentioned, it's pretty tight on PW6/7.
I was asking for tune details from others shooting the 34g pellets because I was wondering if I should be able to achieve my goal of 930-950fps on a lower reg setting than I'm currently at. But tough to compare as it seems not many are using the 600mm barrel. Thank you to everyone that has chimed in so far.
I was asking for tune details from others shooting the 34g pellets because I was wondering if I should be able to achieve my goal of 930-950fps on a lower reg setting than I'm currently at. But tough to compare as it seems not many are using the 600mm barrel. Thank you to everyone that has chimed in so far.
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You should be able to achieve that with a 600 at lower reg pressure 600 mm is about 24 inches and I think the maverick has a pretty big plenum probably could at 130 or even 125
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I tried to base my current tune off the AEAC power tune for the 34gr pellet. He was shooting a 700mm sniper, with second reg at 130. My assumption was since I have the shorter 600mm barrel I'd need a higher reg pressure to get the same results. His tune had regs at 155/130, now I'm at 170/140.
I was able to achieve my target speed with a lower reg pressure, but I could tell the gun was less happy. It was much louder. Now it quieted down so much that you'd assume velocity took a big drop, but it hasn't. I have officially learned the "sound" of an ideal tune. Happy with my results so far, more testing to come this weekend!
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That's good sometimes a quick blast of higher pressure is a better way to go with a shorter dwell time on the valve
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Good post. For squirrel hunting it would be nicer to have a 600mm barrel where I hunt over the 700mm Maverick. I have the same setting on my 25cal Sniper at 170/145 and it will max out at 1032fps with JSB King Heavies MKII's. That is with the Tungsten hammer weight. I noticed that in Ernest Rowe's video that he achieved the same speed at 180/150bar. I have an extra 600mm barrel but its in 22cal.
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I'm right at 950fps now, but the IHS is not maxed out, so I could push them faster if I wanted to. I've found the accuracy is best with my 600mm barrel if I keep them at or under 950.
I also have a 600mm 22 caliber barrel with probe! I was shooting the 25.4gr monsters at the same speed (950fps) and groups were VERY tight. I'd say slightly better than I'm getting now in 25 caliber. But I wanted more energy on target for the medium size pests, hence the upgrade to 25 caliber. That's also why I'm trying to push the 34's faster.
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I just did some chrono testing and noticed I drop about 40fps as I go down the different power wheel clicks. With the 34gr pellet on PW7 I'm at 950, PW6 is 910, PW5 870, etc. Does that sound about right? If not, what should I be aiming for?
FWIW I didn't test all 7 power wheel settings, just 4-7.
FWIW I didn't test all 7 power wheel settings, just 4-7.
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My impact likes the 34 gr mk2 pellets at 905 910 ish or a little slower but I'm using superior heavy 1 in 18 twist in mine
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Be careful with the IHS and power wheel setting. Increasing can cause problems. If you get too much dwell on the valve opening you can get too much air in the barrel and wash the back of the pellet after it leaves the barrel. This will cause accuracy issues, larger SD’s and lower shot counts.
Mine is a Compact so I need a very short burst if air.
Mine is a Compact so I need a very short burst if air.
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Maverick. VP 600
HSA Hammer Micro internal adjustor 20.34mm
Hammer Macro / wheel # 5
120 Front
78 . Rear
JSB Match Diabolo Exact King .25 Cal, 25.39 Grains, Domed,
937 fps SD of 2.or less and dime size groups at 25 yard.
HSA Hammer Micro internal adjustor 20.34mm
Hammer Macro / wheel # 5
120 Front
78 . Rear
JSB Match Diabolo Exact King .25 Cal, 25.39 Grains, Domed,
937 fps SD of 2.or less and dime size groups at 25 yard.
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Just an update, I ended up backing the velocity down by turning in the IHS one full turn. The 34gr's grouped better for me at 930fps vs 950fps.
I had a neat discovery when switching back and forth between my two primary pellets, the 34gr FX and 26.54gr Hades. I shoot the 34gr on PW7, and back it down to PW5 for the lighter Hades pellet. No matter the state of tune, I get the same velocity on both settings. It's made it easy for me to know what velocity the Hades will be shooting at when tuning with the 34's on PW7, since it ends up being the same. Of course I still end up double checking with the chrono, but it's been a consistent finding.
Also the Hades appear to group a tad bit tighter at 930fps compared to 950-955fps. I'm only shooting out to 35yds at the moment, but both pellets are grouping into one ragged hole when I do my part. On PW7 with a 480cc bottle I'm getting 55 shots before reaching my second reg pressure of 140 bar from a 250 bar fill.
I had a neat discovery when switching back and forth between my two primary pellets, the 34gr FX and 26.54gr Hades. I shoot the 34gr on PW7, and back it down to PW5 for the lighter Hades pellet. No matter the state of tune, I get the same velocity on both settings. It's made it easy for me to know what velocity the Hades will be shooting at when tuning with the 34's on PW7, since it ends up being the same. Of course I still end up double checking with the chrono, but it's been a consistent finding.
Also the Hades appear to group a tad bit tighter at 930fps compared to 950-955fps. I'm only shooting out to 35yds at the moment, but both pellets are grouping into one ragged hole when I do my part. On PW7 with a 480cc bottle I'm getting 55 shots before reaching my second reg pressure of 140 bar from a 250 bar fill.
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Just wanted to update this thread in case anyone comes across it via searching in the future.
I found the reason for my tuning struggles, specifically not being able to start low on the reg and slowly walk my way up in velocity bumping up the reg 5 bar at a time while having the IHS maxed out. All with the idea of over shooting my velocity goal, then adjusting the IHS to bring the velocity back down.
I just took my Maverick apart to investigate and low and behold, it had the 13.4g hammer weight installed! A massive "ah ha!" moment. I had just "assumed" it had the correct weight installed from the factory. Thankfully I had the proper hammer weight (11.4g) so I swapped them. Now the tuning is working as it should, but definitely starting back from scratch.
The one good thing is now I have the heavy hammer weight if I decide to pick up a superior heavy liner and shoot heavy slugs in the future.
I found the reason for my tuning struggles, specifically not being able to start low on the reg and slowly walk my way up in velocity bumping up the reg 5 bar at a time while having the IHS maxed out. All with the idea of over shooting my velocity goal, then adjusting the IHS to bring the velocity back down.
I just took my Maverick apart to investigate and low and behold, it had the 13.4g hammer weight installed! A massive "ah ha!" moment. I had just "assumed" it had the correct weight installed from the factory. Thankfully I had the proper hammer weight (11.4g) so I swapped them. Now the tuning is working as it should, but definitely starting back from scratch.
The one good thing is now I have the heavy hammer weight if I decide to pick up a superior heavy liner and shoot heavy slugs in the future.
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