Just went from 18gr. JSB to 25. What’s considered ideal velocity for 25. Gr. MRD pellets in .22 cal. Trying to get to 900fps. Is this to much to ask? Stock maverick 600mm barrel. I’ve maxed out at about 860 FPS. Regs. 140/110 thanks.
Tuning Maverick .22 cal. Tune with 25 gr. JSB redesign
- Thread starter DanH
- Start date
Your current hammer, which is 11+g, will reliably work up to140bar or more. If you haven't already done so, try adjusting the HS grub screw (1.5mm) out ( CCW) a 1/2 turn at a time and see where it plateaus then start bumping up the reg 5bar at a time. Do this until you reach 900. Then increase your reg pressure about 20% and tune back to 900 with the grub screw (CW). Each full turn of the grub is .5mm of preload, Each number on the HS wheel is equal to .5mm of preload. Hope it works for you. My WC MK3 w/700mm is a bit easier to get to 900. I'm tuned to shoot 25.39 @ 930 with reg set to 105bar and my grub is @ 4mm with a 11.275g hammer.
Patrick
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I did not know that that is why I’m asking questions here. A friend just received a Maverick sniper with a 700mm barrel paper work that came with it said it was tuned with 25 gr. JSB pellets@ 906 FPS. We shot 18 gr JSB over chrono @ 1030 FPS avg.
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can’t say for sure what i got for fps with the stock hammer but i know that the 177 and 22 come stock with a 7 g hammer the 25 is 11 and the 30 is 13. also like i said i’m getting 960 with 600 mm and a 25 hammer
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Not necessarily. My Maverick sniper .22 was part of the first batch in October 2020 and it came with an 11g hammer (and not the 20MOA rail). subsequent batches did come with a mix of 7g and 11g hammers (as well as the 20MOA rail). FX has been known to grab whatever is around and handy sometimes.
DanH, if you have a way to weight the hammer and let us know. This is what an 11g and 13g looks like. My WC came with a shorter spring to maintain preload. The longer spring is now standard on all Mavericks and WC mk3.
Patrick
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Mine has a 600mm Superior and shoots the RDMs at about 960 fps. Can go higher but it’s very accurate at 960. Has stock hammer spring and .30 cal hammer (13 gr?). Regs at 185/125. HST has inner adjust backed out to just before it won’t cock at level 7, then backed off to level 4. Make sure you use the S ports on the transfer port. I also have the Huma pin probe since I originally wanted to shoot slugs but couldn’t get the gun to shoot heavier .22 slugs accurately. Will probably end up selling the gun, shoots the RDMs great. Just don’t need another gun that shoots RDMs…
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I’ll check the hammer. Shot friend’s gun today with .25’s avg. @ 860fps. He had a double feed and couldn’t close bolt so I loosened the barrel and slid it forward a couple inches to use a cleaning rod and noticed he was on the S port.
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Ok finally got a chance to weigh hammer it’s 10.53 g. I’m going to try using the the slug port next. If that doesn’t do it I’ll try a,13g hammer. Thanks for all the replies it gives me a lot to think about.
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