Airgun Accuracy

Only accurate airguns are interesting!

JSB Label Numbers Explained

The numbers on JSB produced pellets (also sold under Airarms, Cometa and other brands).
For example on the label on the bottom of the tin:

JSB Exact label on bottom of tin

JSB Exact label on bottom of tin

First number: 8006709
Second number: 6
Third number: 4.51

The first number:
– 8 = number of the pressing die
– 00 = personal number of responsible employee in production
– 67 =personal number of the employee in Quality Control
– 09 = year of production is 2009

Second number: 6 = manufacturing batch
Third number: 4.51 = head diameter in millimeters

The 2013 production year batches I have seen do not show the “personal employee” numbers anymore. They just show zeros at those positions. The number looks like 8000013 for a pellet from pressing die 8 from the year 2013.

Die numbers higher than Die 9 make a the total number an 8 digit number. Like 21 00 58 14 : Die 21, production employee 00, Quality control employee 58, Year 2014.

I for myself ignore the head diameter and just look at the die number when selecting batches for testing.


Pellet head size and weight distribution

I searched the internet for info on the weight and head sizes that are found in a tin of airgun pellets with the same head size and batch number.

H&N FTT Pellet Head sizes

H&N FTT Pellet Head sizes

The above table about H&N Field Target Trophy pellets were measured with a digital caliper. Not by clamping them between the jaws but by lying them on the jaws that were opened to a pre-set distance. No deforming of the pellets this way. Notice that the tin with the 4.52 label has an average measured head size of 4.55 and the tin labeled 4.53 has an average measured size of 4.47. (source:

JSB pellet head size Distribution

Air gauged JSB pellet head size distribution. no.3 = 4.49mm. no. 6 = 4.50mm. no. 10 = 4.51mm. no. 15 = 4.52mm.

The above picture shows JSB Exact pellets that were air gauged. See for more info. The picture shows that the head size varies from 4.49mm to 4.52mm  in one tin.

AA Field Weight  Distribution

AA Field Weight Distribution

The picture above shows the weight distribution of a full tin (496 pellets) of Airarms Field Heavy. These pellets are produced by JSB. The pellets were sorted in 0.02 grain / 0.013 gram groups The lightest pellet is 10.16 grain or 0.658 gram. The heaviest is 10.52 grain or 0.682 gram.  The label says the pellets are 10.3 grain / 0.67 gram.

JSB Weight  Distribution

JSB Weight Distribution

This picture above shows a very good weight distribution of JSB Exact. A narrow and normal distribution with most of the pellets at the average weight.

The picture below shows a bad weight distribution:  A wide distribution with many light and many heavy pellets.

JSB Weight  Distribution

JSB Weight Distribution


15 thoughts on “JSB Label Numbers Explained

  1. Why is the die number more important than the head size?

  2. Hi Eric,
    To answer your question:
    I, and with me many others, have measured pellet head size ourselves. We found that the head size within a tin of pellets has a variation that is quite large. For example: In a tin with 4,52 on the label the measured head size varies between 4,50 mm and 4,54 mm.
    And that is not just a few pellets in that box but 4,52 mm does not even seem to be the average for the head size in that box.
    This means that the head size printed on the label is not a good indication of the actual head size of the pellets in the box. This makes the head size a meaningless figure.

    The Die number gives the relation of pellet to the pressing die that was used for making that pellet. So next time you buy a tin and it has the same Die number the new pellets will at least come from the same pressing die and will have the same average shape.

  3. Ok thanks Sven, makes sense.

  4. One thing is still puzzling me here. If the die is the same but you have different head sizes in one tin, what does the number tell you anyway? If the number is giving you a accurate shot results it makes sense, but still I am a bit puzzled when I start thinking this over.

  5. Hi Eric,
    You are right. It is puzzling that the same pressing die produces different head sizes. And different weights as well.
    This most probably means that the measured head size is not that important for good accuracy. But that there are other pellet parameters that result in a good or bad accuracy.
    What you may want to consider when thinking this over is that you are actually re-sizing the pellet head when you load it in the barrel. And the pellet skirt is even re-sized two times: 1. it gets smaller by loading it into the barrel and 2. It get blown out by the blast of air at the shot.
    I will put up some pictures above to show the differences found in pellet head size and weight within one tin (not mine but found on the internet).

  6. Nice picture on the distributions of the weight and head size. Can it be that because of the speed of production these differences are coming up? I can imaging that due to speed weights and head size are not consistent. And then the question will come up how cirtical the manufacturer has set their criteria for quality control.

  7. Some interesting results, unfortunately leading to still more questions…. !
    Do you know if the die used in the manufacturing process only makes one pellet at a time. If each pressing made more than one pellet at a time, the same die could result in pellets with a different size and weight if for example it makes four pellets at a time and the “pressings” for each one are ever so slightly different.

    Just a thought !

  8. I think the differences some people find between 4.51 & 4.52 are more to do with pellet form and weight distribution from the differing dyes. .01 in lead on a diameter is negligible. It’s a .005mm coating!

  9. I wonder if the production die only has a single forming section. I’m thinking that one die might be making ten or more pellets at each stroke of the press, by having parallel rows of forming sections.

    • Hello Jerry,
      the dies in the JSB factory make one pellet at the time. It is a somewhat slow process but this guarantees quality. So I was told by the director of JSB , Pavel Kolebac.

  10. Very interesting reading..i thank you all for taking time out to try an lihhten us on jsb batches!!!

  11. Hi Sven
    What is the state of the JSB pellets now, is it still bad as when you started measuring?

  12. And yes …are you know for this tips of selection
    “Yrrah roll” on youtube

    • Hi Anto ,
      I’m still shooting my 2009 JSB Exact batch in the Walther LG400. For Field Target I’m now shooting an Anschutz 9015 converted by Jon Harris. Got this rifle in May this year and found that a 2015 batch of the Airarms Diabolo Field gives excellent results in this rifle. These air arms pellets are produced by JSB.
      From what I hear from other shooters at the club I think JSB has released some batches of lower quality in the years 2014 and 2015. I tested a few shots with a JSB Exact batch of 2016 and those seemed to perform very well in a 16 Joule Weihrauch HW50 springer and also very well in my Anschutz 9015 PCP. As far as I know the current JSB pellets on the market from 2016 and 2017 production seem to be of good quality. You still have to select a batch number that suits your own rifle but overall quality and performance is very good.

      Concerning the Yrrah method of pellet selection: I have read about it years ago but I have never tried that. It may be worthwhile for .22and .25 pellets for 100 meter airgunning, as this is what Yrrah from Australia is shooting. For FT I have never heard that anyone does roll their pellets. Most FT shooters, and also the champions, test and select by batch number and shoot these straight from the tin. Without weighing or further selection.

      In my opinion the diameter of pellet head and pellet skirt is not relevant for accuracy. At least not when we talk about the differences within one batch of pellets of good quality. That is because when you load the pellet into the barrel the head and the skirt are formed into the barrel diameter. When loading you size the pellet into the barrel. Especially with the JSB’s which are from quite soft lead. So after loading all pellets will have the same head and skirt diameter. When Yrrah rolling the small 4.5mm pellets you select them based on a dimension that gets altered when you load it into the barrel. that’s why I think its not a worthwhile selection for FT shooting.

      Regards, Sven

    • Here is a freind of mine doing the same test @15:00.

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