My 25 Wildcat velocity varies from 780 to 820 fps with JSB MKII 33.95 gr pellets, this seems like too much to me as vertical stringing per Chairgun indicates this would result in a variation of 1.34" at 70 yds. The rifle has had about 1,500 pellets thru it and has been back to AOA for warranty work on regulator for velocity variation of up to 130 fps and magazine indexing problems. The barrel has been cleaned a number of times with no effect, pellets are unlubed. What is a "normal" velocity variation and what are the possible causes for high variation?
25 Wildcat velocity
- Thread starter osage
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My .25 wildcats velocity is 815 fps with the 33.95 jsb heavies. The shot strings vary from 807 to 822 fps. Your variation does seem like a lot. How does it shoot the 25.4 kings? I also wash and lube my pellets . Are you using the mk1 or mk2? The mk2 don't fit so tight like the original mk1.
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Over how many shots are you measuring the variation and what (if any) mods have you done? i.e. Could you be continuing to shoot once you have fallen off the reg?
What is the variation for the first 20 shots after a fill?
Do you know what the reg is set to?
What is the variation for the first 20 shots after a fill?
Do you know what the reg is set to?
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I believe mine was 12 fps over 40 shots using the 25grn jsbs. I bought the gun used so I don't know if the reg. Was broke in and need to retest.
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Mine shoots them at 792 + or - about 8.
Zebra makes a good point, to which I'll add that my guage over-reads by about 12-15 bar at the 150bar level (it's fine at 230bar!).
Also note that there is often an increase in velocity just as the rifle is beginning to fall off the reg.
So a string done from a low filled and low reading rifle might give your variation.
Zebra makes a good point, to which I'll add that my guage over-reads by about 12-15 bar at the 150bar level (it's fine at 230bar!).
Also note that there is often an increase in velocity just as the rifle is beginning to fall off the reg.
So a string done from a low filled and low reading rifle might give your variation.
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Normal fill is 230 bar, when my tank gets low I fill to 200 bar. The regulator seems to be set at 140, at my normal shooting distance of 70 yards I get a steady increasing drop at that point. All of the gauges seem to read about the same. Haven't tried the 25.4 gr across the chrony lately as they aren't as accurate in my rifle. Typical string from 230 bar fill with MKII's : 812, 812, 782, 808, 807, 805, 811, 811, 818, 823, 811, 812, 820, 811, 815, 812, 795, 791, 804, 801.
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Seem to have the same problem. At 230 bar it shoots 920 fps when it gets down to 190 bar it evens out at 887 all the way to 140 bar. After it sets for a few hours the first shot comes out really hot. I am shooting the 25.39 JSB
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sometimes this happens due to valve. Clean and lube the valve, check for any leaks from the vent hole or the barrel and try again.
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Apart from the 2 slow (emboldened) shots, the string is pretty respectable. Certainly not a deal breaker.
If you were using a Combro chronograph, I would ask the distance between muzzle and first sensor, as in humid air, you can get steam causing the odd low reading if the sensor is too close.
I am not familiar with the chrony (is that a brand?).
You rightly say that Chairgun indicates you'd get a fair amount of vertical stringing with that velocity variation, but do you actually get stringing on your targets?
You might be pleasantly surprised, if this is a measurement issue, rather than a real velocity issue....
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Yes I do get stringing, that's why I checked the velocity. Overall I'm real happy with the Wildcat and am pleased with the accuracy until the unexplained stringing started to show up. I've noticed a number of shot strings posted on the internet that have less variation from unregulated guns so it seems reasonable to expect better from the Wildcat.
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