I got a M3 about 1 month ago and tuned it perfectly at 907 FPS MOA @ 100 yard. I had several tin of MK11's from 7 or 8 month ago purchased from Midway USA to tune the gun. Same pellets arrived at Utah Airguns and they were able to fill my back order from several month ago. The new ammo will struggle to shot a 2" group at 100 yards and occasionally a flyer more than 3" out of center. Any one having problems like this with the recent batch from JSB ?
JSB 25 cal 34gr MK11 issues
- Thread starter Stealth
- Start date
Do you sort your pellets? Have you received any damaged tins? Have you tried weighing the pellets in question to see if they consistently weigh the stated weight (within reason) on the labeling?
I’ve noticed flyers out of my groups today as well as the over the weekend. I attributed it to human error and not sorting pellets, but I kept getting at least one odd flyer. Generally if my aim is off then I’ll send more than one pellet to the same spot before making a correction. I don’t feel confident blaming the flyers on a batch of pellets. I recently have been shooting them at a faster speed than usual and I’m no crack shot. I shot them from a Brocock Bantam Sniper.
I’ve noticed flyers out of my groups today as well as the over the weekend. I attributed it to human error and not sorting pellets, but I kept getting at least one odd flyer. Generally if my aim is off then I’ll send more than one pellet to the same spot before making a correction. I don’t feel confident blaming the flyers on a batch of pellets. I recently have been shooting them at a faster speed than usual and I’m no crack shot. I shot them from a Brocock Bantam Sniper.
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I bin weigh and size mkII's for my RAW. Tin I am working out of at present is labeled "34.30-34.48gr 6.37mm washed/pledged". I get fliers, not many, but often enough to be annoyed with myself. Batch 69060021-0-6.35. Die number 69.
edit: When they become available again, try a couple tins of Rangemaster Emperors, the Daystate mkII "equivalent."
edit again: BTW, the FX 33.95gr diabolos are what might be considered the JSB original "mkI equivalent." These perform very well from a TalonP.
edit: When they become available again, try a couple tins of Rangemaster Emperors, the Daystate mkII "equivalent."
edit again: BTW, the FX 33.95gr diabolos are what might be considered the JSB original "mkI equivalent." These perform very well from a TalonP.
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I have noticed pellets rarely weigh at the claimed weight. Lately they seem to vary by as much as a full grain light or heavy, usually light. I weigh to thousandths of a grain (my scale weighs to two thousandths) and shoot from bins of similar weights. This seems to eliminate most (but not all) fliers.
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We are lucky of beeing able to blame the pellets and the rifles.
Other way the concept of ourself could be depreciated.
Other way the concept of ourself could be depreciated.
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I've weighed more than one tin of JSB's. about a 5%variance seems to be normal. Last tin was 33.2 to a bit over 34.6 with some outliers lighter and heavier. That's enough for a 20+ FPS difference and over 100 yards, enough to drop an inch. Once I started weighing to 1/10 of a grain, accuracy really picked up. I didn't believe it till I tried. Weighing and grouping pellets into weight groups does work.
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Those that weigh near the published weight get smaller bin/group ranges, like 33.92-33.96, 33.98-34.02, 34.04-34.10, .10-.20, &c. The major outliers are fed to a TalonP. Eliminating some of the variances leaves it on me to make up the difference -- practice and more practice.
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This week I have received several boxes of this new Slug MK II from JSB .25 for my impact MK II.
I thought that these would behave better than the previous ones, and the truth after many configurations, the results are fair.
I'm testing from 900fps to 1000 fps and at the moment the best is about 970fps ..... at 91yards
I thought that these would behave better than the previous ones, and the truth after many configurations, the results are fair.
I'm testing from 900fps to 1000 fps and at the moment the best is about 970fps ..... at 91yards
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I had a post two weeks ago and my impression was that I am an isolated case.
JSB .25 cal 33.95 gr MK2
My 2020 batch - washed, weight sorted an lubed was about a 1.5" footprint @ 100 meters including occasionally flyers.
The new batch from May 2021 is terrible and more then F terrible POI and the flyers missing the paper high-left.
And btw the .25 skirt I am measuring is 6.6 + mm doesn't even fit my pellet sorter plate anymore (I bough it last year to sort my pellets dedicated for competition) ...
Edit:
Fx Impact .25 MK2 PP 700mm STX-A liner
910 fps with old 2020 batch
870 to 920 fps not working with the new batch
JSB .25 cal 33.95 gr MK2
My 2020 batch - washed, weight sorted an lubed was about a 1.5" footprint @ 100 meters including occasionally flyers.
The new batch from May 2021 is terrible and more then F terrible POI and the flyers missing the paper high-left.
And btw the .25 skirt I am measuring is 6.6 + mm doesn't even fit my pellet sorter plate anymore (I bough it last year to sort my pellets dedicated for competition) ...
Edit:
Fx Impact .25 MK2 PP 700mm STX-A liner
910 fps with old 2020 batch
870 to 920 fps not working with the new batch
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That is interesting, that they may be varying in weigh more nowadays. I have never weighed pellets, being a hunter not a target shooter.
Do you think that quality is slipping overall?
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It is very clear that new products come onto the market every day and I see higher quality in them such as Zan Proyectiles ..... super clean and with a very good quality control ...... and the good surprise is that they group magnificently !! The H&N work great for me too
I am thinking of rectifying a few slugs to just 249 and trying ..... I am not amused by that invention of the skirt of these new slugs ........ previously I have rectified the other Knock Out 251 to 249 and he I like my Superior Heavy liner much more, having good results.
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Well, nothing I have rectified and worse ...... these slugs from minute one you have the feeling that it will not work ... well that. I am going to try another day with different moderators of friends who still improve something with the change of harmonics ;(
I have rectified and worse ...... these slugs from minute one you have the feeling that it will not work ... well that. I am going to try another day with different moderators of friends who still improve something with the change of harmonics ;(Upvote 0
I've had much closer tolerances with FX than with JSB. Just saying. I don't, normally check diameter, so that could be a factor. Yes, I use a scientific scale because I'm anal that way 
but I also get ES of 10 or less and SD as low as 2-3.
but I also get ES of 10 or less and SD as low as 2-3.Upvote 0
Went back to the earlier tins of 34grain, accuracy returned! Guess I can use they last batch for squirrels out to about 30 yards LOL
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