Hi Guys, I've got a Mk2 Crown In .22 with 380mm barrel shooting jsb 18gr pellets. Anybody with same setup, what speeds do you shoot the 18gr for best accuracy??
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FX Crown .22 380mm Favourite Speed
- Thread starter fiestaman
- Start date
Mine likes them right around 880 or so...Thansfer port is at medium and I think my hammer wheel is 5....I did take the rifle apart and adjusted the hammer spring before tuning the rifle...On max transfer port and hammer wheel on the highest number I can shoot the H&N 21 grain slugs at the same speed.
Tony P.
Tony P.
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Surprisingly, mine likes 18.1 gr pellets at 970 fps. I never expected it to shoot that good at that speed. JSB 18.1 gr pellets seem to be the sweetheart for all FX .22 cal rifles straight from the factory.
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Thats very close to the speed I shoot them out of my impact m3. So the FX superior liners like them fast.
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my crown with the 380 barrel liked 905 910 the best with the 18 grains. i did not try it higher but guess i will check it out soon lol.
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How does the 380 mm barrel compare to the 500mm in terms of accuracy or consistency? Less POI shifting problems , maybe ?
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I have both and they both do well the 380 and the 500. For me i found it to be in the tuner lol. anything longer on a crown {for me } is just to awkward to carry around in the woods which is what i am doing with mine. It will be fine on the bench if you truly have great tuning skills and knowledge of what is happening with everything. This is only my personal opinion and may not be the same for all.
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I have two crown mk2 and barrels that run 380mm, 600mm and 700mm. I see no difference in accuracy between them and I dont suffer poi problems on any of them. I had poi shifts when I bought them brand new so I puled the shrouds and looked at the spacers. I adjusted them since they were all bunched up closer to the breach. I got great accuracy then the poi shift started coming back within a couple groups. I took the shroud off again and found the last spacer had worked its way back down almost to the second spacer. So I wrapped electrical tape around the liner to form a stop to hold the spacer in place. No more poi shift after that and I had to do it on every barrel.
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) you can also install the carbon fiber stiffener over the liner to achieve the same results but it takes a lil more modding effort on the ultra light systems
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Wow, that's fast, what reg settings are you on. Any other mods to get that speed with the 380mm
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Thanks guys, running at 150bar and shooting at 970 fps must be on the limit at that stage, is the gun not jumpy and loud. My method of tuning was to shoot the 18gr somewhere between 880-900. What I do is max out hammer and preload to the point the wheel turns freely but not tight. Then adjust up reg until I hit about 20fps more than I require, then dial back hammer until I get to 900, then shoot groups on each hammer setting from 900 down to 880. Anybody else tune this way.
What is shot count like shooting at 970, would there not be a lot of waste air
What is shot count like shooting at 970, would there not be a lot of waste air
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970 fx newer liners seems to like faster speeds it seems, 930 seems to be a sweet spot iv found on my fx guns 177-22 cal
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Efficiency in 380mm seems to fall on it's face much past 930fps, so that's the fastest I go. By efficiency, I mean the amount of air i'm dumping down the tube versus how much increase in velocity I get. Volume of report will also tell the tale. Accuracy will largely depend on your tune. Newer STX barrels don't seem to care much about what speed you shoot. But harmonics will do their thing reguardless. You have to find the sweet spot for YOUR gun.
FWIW I keep my gun tuned so the lowest setting is 650fps. I actually do most of my shooting at this speed. Extremely quiet, accurate, and absurd shot count.
FWIW I keep my gun tuned so the lowest setting is 650fps. I actually do most of my shooting at this speed. Extremely quiet, accurate, and absurd shot count.
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