8.4 grain JSB and AA pellets visually compared.

[nced]

I haven't accuracy tested both labels however the 8.44 grain 4.52mm JSB Exact pellets are very accurate from my R9, but I did buy a tin of the 8.4 grain Air Arms "Diablo Field" pellets to compare when I get a chance.

Visually the two pellets are almost identical which I guess is to be expected since I've read that the AA pellets are made at the JSB factory with AA dies. When visually comparing the two brands I did notice that the AA version pellets have visible parting lines and the JSB brand pellets don't. Here is a pic comparing the two......
Uploaded at Snapagogo.com
The difference probably isn't an issue, but the pic does show that the AA label pellets aren't simply rebadged JSBs. Anywhoo...the parting lines from the AA dies do indeed show up faintly in the pic.

[Bwalton]

I did a test on the two,  the AA are a little longer, that I can recall,  they shot better in. 177 in that weight,  but not better then JSB in .22 and up

[gard72977]

I have a HW77 that shoots the JSB ok but really stacks the AA 4.51 in a neat little group.

[michaelthomas]

Here is a picture of a JSB 8.44 on a 100x optical comparator.  You can measure angles, radii, and distance to a few ten thousandths pretty easily.  What I find interesting/disappointing is the great differences you will find in the pellets you buy today, and the ones you may buy in 3 months.  Skirt angles, dome radius, dome height, head diameter, skirt diameter, waist diameter, length, cavity depth/width.  I'm mostly surprised because the tolerances that are accepted for the manufacture of the dies must be really loose.....or maybe they are experimenting with different shapes all the time.  I'm certain that if a person wanted to, they could produce dies within tenths of the originals.....but they don't seem to.  They are constantly changing.  I don't believe that wear could possibly account for the changes, either......some of them, but not all of them.

The dies are certainly made by cnc....so it seems strange that they vary so much.

Oh, BTW.......the size designation on the tins is meaningless.  If 4.52's are working for a particular gun.....it's doubtful that it's because the gun likes pellets that are 4.52.  There are surely some that might average 4.52.......but it's usually no larger of a percentage than 4.51, 4.50.....etc.


Mike

[nervoustrigger]

Pictured below is a comparison I did a little over a year ago.

In general I find that one of the JSB or Air Arms 8.4gr or 10.3gr pellets will group best in most of the rifles I've tested.  A given rifle's preference tends to drift between these over time, perhaps because of the batch-to-batch variations that Michael describes.

[Froghunter]

Just a quick couple of questions: How are these pellets make and what do the pellet dies look like?

Thanks,

Froghunter

[nced]

Very intere

Pictured below is a comparison I did a little over a year ago.

In general I find that one of the JSB or Air Arms 8.4gr or 10.3gr pellets will group best in most of the rifles I've tested.  A given rifle's preference tends to drift between these over time, perhaps because of the batch-to-batch variations that Michael describes.

sting! I just took a pic of a AA and JSB side by side and indeed the cavity is a bit different but not as pronounced as your pic.......
Uploaded at Snapagogo.com

[gard72977]

That AA looks a bit lighter in the rear.

[michaelthomas]

If you take pictures of the cavity from each new batch of pellets you buy over time.....you will find that the AA and the JSB each have every imaginable skirt cavity proportion, and that no particular characteristic can be said to be exclusive to either.  I have JSB's that look just like the AA's in the picture and vice versa......and some that are greatly different and not really comparable to either.

Some pellet batches are also much more "round" than others.  It is not uncommon for a pellet to measure 4.50 across one side, and 4.52 or 4.53 90 degrees from that point.  The better ones only vary by .01mm.....or about .0004".  I also have use of a Mitutoyo lase micrometer that will measure out to the millionths of an inch without touching the pellet.  Last winter I spent a ton of time analyzing nearly every pellet I could find.  The pellets all have to be cleaned in an ultrasonic tri-chlor bath prior to measuring, because the laser will pick up the slightest amount of debris on the pellet.

The dies used to make the pellets are 4 pieces.  Top (head), bottom (skirt cavity), and the split halves that form the waist.  Bits of lead wire are cut to length then forced in via the head end.  There is no provision for bleed off or overage in the die....that's why they try to do a very precise job of precutting the lead wire.  The small variance ends up showing in the skirt base.  When putting a pellet on a ground base to view on the comparator......you can almost always see daylight under the pellet because the skirt bottom is not flat or actually perpendicular to the centerline of the pellet.  Kind of makes you wonder why we bother to make a crown exact to bore centerline, when the pellet that we are going to be shooting is not able to take advantage of it, anyway.

Mike

[Sfttailrdr46]

  I would think that the best performing and possibly more forgiving rifles are those made to very tight tolerances then the slop introduced by the pellets is less of an issue. However it does explain why some guys weigh measure and sort their pellets so that when they are competing the shot to shot performance is consistent due to their diligence

[Tom SC]

 Wow Mike thats good stuff. I feel a little silly now. I use to say my rifle shoots AA's better than JSB's but heck it sounds like I have no control over what I'm putting in the pipe. Oh well more to ponder

[grauhanen]

Wow Mike thats good stuff. I feel a little silly now. I use to say my rifle shoots AA's better than JSB's but heck it sounds like I have no control over what I'm putting in the pipe. Oh well more to ponder

I have rifles that shoot the same head size AA's and JSB's with different results.  They can even chrony a little differently -- not by much but a little.

[Booger]

Wow Mike thats good stuff. I feel a little silly now. I use to say my rifle shoots AA's better than JSB's but heck it sounds like I have no control over what I'm putting in the pipe. Oh well more to ponder

I have rifles that shoot the same head size AA's and JSB's with different results.  They can even chrony a little differently -- not by much but a little.

My TX200 use to shoot AA better, now she likes H&N FTT better. I guess it is the luck of the draw.