JSB mk2 pellets weight. High 35.1gn low 32.9gn

Jump to latest Follow Reply
B

Birdslayer25

Member
Aug 11, 2017
157
2
MO
I weighed out an entire ten of JSB heavy pellets. The lightest pellets weighed 33.3 grains. The heaviest weighed 34.7 grains. Thats a big variation especially for us long range shooters.

I haven't had a chance to run them over a chrony yet after being sorted by weight. By the way my scale is very accurate I have some 44gn NSA slugs they all weighed exactly 44.0gn there 25 in the package. 

Almost a 1.5gn weight difference in the JSB's should equate to some pretty big effects at 100 yards. Also the shot string will be effected quite a bit to. 

What kind of speed difference is there from a 33.3gn pellet to a 34.7gn? 
 
Hi Birdslayer25,
Good questions. MKII’s shoot very well out of the tin at 50 yards/830fps. When the weather improves, I’ll stack wood for stops at 75 & 100 yards. I’ve weighed one of the MKII tins that Santa brought: lightest = 33.44gn........heaviest = 34.50gn........average = 33.97gn......252 pellets are within 1% of 33.97gr. That’s very good for 5-6 cents per pellet. Will be fun to learn what’ s good enough. The 44gn NSA slugs are 20-26 cents each.
When the weather gets tolerable, the chrony, stand, and toys will come out to play. Other things to try......wash, lube, size, roll.........I’ve never tried 100 yards. I think I’ll let my gun down.....it’s better than me.

Happy New Year
 
Upvote 0
Yeah for the price you cant complain there a good pellet they shoot very good out of tin. But for them longer shots they need to be weighed and sorted.

Also for someone trying to get the tightest shot spread the pellet weights are gonna make you crazy.

Not that it can't be done but shooting with one pellet weight your gonna be able to find perfect harmony with the reg much easier.

I've weighed and sorted several tins I'm gonna tune my impact tomorrow to see if I can get it really precise. That's if I get time to do it.

HAPPY NEW YEARS!! 
 
Upvote 0
I just finished shooting with my JSB mk2 heavies after sorting them by weight. The results are pretty big. I have the pellets sorted from 33.3 to 34.7. All have been sorted out to weigh within a tenth of a grain. 

My impact will shoot the 33.3 grainers at 865 Fps. Shot string over 25 shots was a high of 865 and a low of 863. It's unreal how consistent they shoot after sorting. 
I did this will all weights from lowest to high all with same results 25 shots 3 to 4 Fps spread. But by the time I reached the 34.7 grain pellets I had lost 12 to 14 fps.

Then I shot at 120 yards to test accuracy with each pellet weight. This made a huge difference for me and I'll never not sort pellets anymore after this. I noticed the lighter pellet shot better for me. From 33.3 to 33.9 these were giving the best groups. 
34.0 and beyond were a lot more apt to spiral. The 34.0 weren't to bad but 34.1 and higher were not so good.

Shooting longer distance I could see the weight differece show up on the target. The Poi begins to get lower with the heavier pellets. Idk about you guys I hope you try this it works. 

I was shooting 120 yards and the groups were insane it was stacking them out to 120 for the most part. By shot 16 groups were opening up to 1.5 inches. But this is still very good. I think if I were to examine skirts for deformaties it would be the last part of the puzzle. 
 
Upvote 0
70 percent of the tin were good. But I would much rather JSB offer a higher quality pellet for more money. I telling ya this 1.5 grain difference in pellet weights is gonna kill you at long range. I weighed a few more tins out this even. I had a low of 33.1 and high of 34.8 that is so bad for long range shooting. Not to mention the guys trying to get there gun tuned in will never get it perfect. 
 
Upvote 0
With the NSA ammo out there and fx having the new barrels. If they perfect those too JSB will be doomed. After seeing the results today I'm really anxious to get a stx barrel so I can shoot more qaultiy ammo. JSB is good for a cheap source of ammo but it has a lot of room for improvement. We shoot high end guns I want high end ammo too. I shoot a lot just because I wanna be the best but I can only be as good as ammo allows me.
 
Upvote 0
I too have weight sorted lots of MKI's. My results for the extreme spread are very similar. Usually 15-20 that are 33.5 and below, the majority between 33.6 to 34.6, On the high end, there are only a few weighing 34.6-34.8. I normally sort the 33.6-33.9 into a group, the 34.0-34.3 into another, 34.4-34.6 into the last shootable group. You can use the extremely high and low ends for re-seasoning your barrel. I also keep one of the 33.5's and a 34.7 or .8 out and use them to recheck the scale throughout the sort of a tin.

Plugging in Birdslayer's velocity extremes of 864 and 851 into Chairgun on a 60yd zero, out at 100yds than comes out to b a .31" drop. Throw in some damaged skirts and that can open the groups up even more. I normally run all my pellets through a .252 sizing die that will get all the pellet's skirts at least the same size to start with. I think it helps some. The next step if desired could be the Yrrah roll or head size sorting with some method. All very time consuming and unless you shoot on a perfectly calm day all this effort is mostly wasted time. Wind speed and direction is the biggest accuracy killer. But heck, this time of year when the weather is so bad you don't want to go out this is good way to pass the time...
Jimmy
 
Upvote 0
"jking"I too have weight sorted lots of MKI's. My results for the extreme spread are very similar. Usually 15-20 that are 33.5 and below, the majority between 33.6 to 34.6, On the high end, there are only a few weighing 34.6-34.8. I normally sort the 33.6-33.9 into a group, the 34.0-34.3 into another, 34.4-34.6 into the last shootable group. You can use the extremely high and low ends for re-seasoning your barrel. I also keep one of the 33.5's and a 34.7 or .8 out and use them to recheck the scale throughout the sort of a tin.
Plugging in Birdslayer's velocity extremes of 864 and 851 into Chairgun on a 60yd zero, out at 100yds than comes out to b a .31" drop. Throw in some damaged skirts and that can open the groups up even more. I normally run all my pellets through a .252 sizing die that will get all the pellet's skirts at least the same size to start with. I think it helps some. The next step if desired could be the Yrrah roll or head size sorting with some method. All very time consuming and unless you shoot on a perfectly calm day all this effort is mostly wasted time. Wind speed and direction is the biggest accuracy killer. But heck, this time of year when the weather is so bad you don't want to go out this is good way to pass the time...
Jimmy
Click to expand...
I have set up my tins the same way after sorting by weights. This helps tremendously at further distances. I just wish JSB would fix the issue. It's gonna be so nice when the new bullet projectiles are paired up with the STX barrels. I expect to be popping birds well over 150 yards. I was weighing some new tins of mk2 and I had a high of 35.1 grains and low of 32.9. That is just messed up. The rest of the airun community needs to recognize this problem. That is pretty crappy quality if you ask me. 
 
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu