I've measured 5000 8.4 grain JSB Exacts supposedly 4.52mm. Here's what I found..

[nced]

First a couple disclaimers......
1. I do realize that measuring pellets heads with my new iGgaging digital calliper isn't an EXACT measurement, especially down to .01mm.
2. Each of 5000 pellets were measured at two points at a 90 degree interval and I am aware that measuring at different points on the head of a pellet would probably give different values, especially for the "second metric digit after the decimal point".
3. I'm aware that different pressures applied to the pellet head with the calliper will distort the measured value at the "2nd decimal point" so care was taken to only apply enough pressure to lift the pellet with the calliper jaws. I also can verify that the difference of only .01mm is enough variation to actually lift the pellet clear of the measuring surface or having the pellet "slip around" in the calliper jaws when lifting so it really wasn't too hard to get a handle for consistent pressure on the calliper "adjusting wheel"!

The reason for these marathon measuring sessions was the simple fact that the tins of Exacts I was shooting from gave a rather variable fit to the leade of my R9 and recently I had a few actually "flip out" of the leade when closing the barrel leading to two dry fires. First I got out the micrometer set I owned before owning the Starret and used the 1" "gage pin" to check the accuracy of my iGaging digital calliper.......
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LOL....it does seem that my digital calliper is off .0005 but it's close enough for the purposes of find out how "oval" my JSBs were! I sorted the pellets in tins by "max pellet head dimension".

When measuring the pellets I would measure the head, then rotate the pellet 90 degrees and measure it again. I used this measuring method.....I marked the calliper jaws so the pellets would be in exactly the same "register" on the jaws. The pellet was resting on the smooth Formica desk top surface and the calliper was flat on the desk top. The calliper jaws were then gently closed on the pellet with only enough pressure to lift it....
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Ok, now on to what I found....
All tins of 8.4 grain JSB Exact pellet tins are labelled 4.52mm but after sorting several thousand pellets only about 1 1/2 tins of pellets were actually 4.52mm, and all of the 4.52s were the 4 unopened tins in the upper right hand cornet of the pic.  I first measured the remaining pellets from the tins I bought after switching to JSBs finding that while they were undersized, very few were actually round within .01mm. Most were oval by .03-.05mm and NO TIN from the "die lot stamped" tins contained a single pellet that measured the listed 4.52mm, even in the "fat dimension". Here are the measured pellets left over from my initial JSB Exact order with tins having a die lot number sticker on the back. The pellets on the left side of the line were all oval by .02mm or more and the ones on the right were "round" within .01mm.....
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Notice that I marked these pellets with a "V" for "variable" if the pellet heads were oval by .02mm or more. Also notice that most of these pellets had a max head width of 4.50mm. LOL....I even had one Exact from tghis lot with a head measurement of 4.42mm x 4.46mm! I'm bettin' that the pellets that flipped out of the leade of my R9 when "latching up" were similar!

Just for grinns I decided to also measure pellets from the 4 unopened tins bought a few months later and found it interesting that these tins had no die lot number sticker, only a sticker like this.....
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After opening and measuring the 4 unopened tins I found that this lot of pellets was very consistent and almost all were within .01mm max deviation! Matter of fact, a rather large percentage actually measured "round"!. By the way, the 1 1/2 tins of sorted pellets actually measuring 4.52mm and 4.53mm all came from the sealed tins without a die lot stamp.........
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Bottom line......after a few days and quite a few hours measuring the heads of JSB Exacts with listed sizes of  4.52mm I'm convinced that I've been shooting from very "sub standard" tins of Exacts since I switched from CPLs since I hadn't shot from the later tins that measured much more consistently.

The reason for switching from CPLs to the Exacts was due to the last two cases of CPLs I received having excess parting compound on them which required washing before lubing. Well....washing and lubing CPLs is certainly a lot less hassle than measuring the pellet heads of every JSB Exact twice 90 degrees apart to sort out the undersized pellets, even with the more consistent production lots!

Anywhoo.......I'm considering reverting back to CPLs even if they need washing before lubing!

P.S. An update after actually shooting a few short range 18 yard targets with the sorted Exacts........
Well.....the JSB pellet measurements have been verifies as it Exacts fit in the leade of my .177 R9 barrel. I shot a few groups upstairs at 18 yards using the pellets with greater than .01mm "ovalness" and they were pellets with 4.47mm max diameter, 4.50mm max diameter and 4.51mm max diameter. As suspected, at only 18 yards I couldn't detect any difference in group sizes except for the pellets with the variable 4.47mm max head size which did show an increase in group size relative to the other sorted sizes. Matter of fact, when loading pellets from the 4.47mm "V" tin I had a pellet fly from the leade when latching the barrel so I'm pretty sure that the two dry fires I had was due to loading pellets directly from my pellet pouch which were dumped directly from the old Exact lot tin.

Even when loading and shooting the "round" JSBs from the 4.49mm (there was only one 4.47mm pellet in the new tins), 4.52mm and 4.53mm sorted tins the accuracy was similar at only 18 yards with the 4.52mm lot shooting a bit tighter group. Looks like the distance will need to be stretched to at least 30 or 50 yards to determine any difference in grouping with my style of shooting. I do know that the fit in the leade was noticeably different between the different sorted sizes and also very consistent.

The fly in the ointment of all this measuring is all pellets in a tin will need measuring to weed out the 4.47mm size pellets, even if all the other sizes are equally accurate.

By the way, I also shot a group at 18 yards with 5 left over CPLs that measured 4.54mm-4.55mm and noticed that I forgot how tight they fit the leade of my R9! Also, the group shot was the equal of the JSB Exact 4.52mm size pellets. Anywhoo...here is a scan of the 18 yard target shot but I really wasn't shooting well from "bucket and sticks" so don't get too anal about the groupings. Basically the target shows that at only 18 yards all groups were similar except the group shot with the "oval" ("V") 4.47mm pellets.....
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[Anylizer]

  When you close your eyes, do you see nothing but piles & piles of pellets & digital calipers???  LOL

 I admire your determination! had to be MIND NUMBING....

[nced]

  When you close your eyes, do you see nothing but piles & piles of pellets & digital calipers???  LOL

 I admire your determination! had to be MIND NUMBING....

Actually....not too bad but I really don't want to do it for each 4 pellet tin order! To keep the monotony down I would play YouTube metal machining videos while measuring the pellets.

[hoffy43]

Hum! That's interesting. Were did you purchase them from? AOA has them on special, buy 4 get 5Th free. they are $9.50 a tin and I believe $12.00 to ship. That's 50 bucks for 5 tins at your door post.

[nced]

Hum! That's interesting. Were did you purchase them from? AOA has them on special, buy 4 get 5Th free. they are $9.50 a tin and I believe $12.00 to ship. That's 50 bucks for 5 tins at your door post.

The first couple "4 tin orders" were bought from Pyramyd Air with their "buy 4 pay for 3" deal plus the 10% discount code. Those tins had the die lot stickers on the back that were covered with the PA code sticker. They're also the pellets that gave an extremely variable fit in the leade and none that were actually 4.52mm in diameter.

The last 4 tins I bought were from Trenier Outdoors and they had only an attached label on the back of the tins with no die lot number. These later Exacts were considerably more consistent than the first couple lots I bought which had die lot numbers. Also, the 1 1/2 tins of pellets that actually measured 4.52mm all came from the 4 tins bought from Trenier.

[Chuy702]

I admire your patience and dedication. Can't  wait to see results  from 30-50 yards

[Regulatori]

Interesting findings. Someone needs to build an automatic sorter that gently measures the pellets and puts them in different trays.
When I got my first set of digital calipers and my .001 gram scale, I lost track of the amount of things I would randomly weigh/measure. I play steel tip darts at a higher level and found myself weighing/sorting my stems/flights (the plastic section and the wing) by "matched sets." haha


Maybe I need to go up to a larger head size for JSB's. I have BS4/FWB 300S and cannot get good results from either the 8.4gr or the 7.87gr JSB's...even 15-20yds look like a 2" wide shotgun pattern.
Soon as I go back to my trusty Meisterkugeln 8.2gr, it's doing ragged one hole groups again.

What was the accuracy difference in your gun when comparing the smaller sized JSB's? Was it a subtle difference or quite significant?

[nced]

Interesting findings. Someone needs to build an automatic sorter that gently measures the pellets and puts them in different trays.
When I got my first set of digital calipers and my .001 gram scale, I lost track of the amount of things I would randomly weigh/measure. I play steel tip darts at a higher level and found myself weighing/sorting my stems/flights (the plastic section and the wing) by "matched sets." haha


Maybe I need to go up to a larger head size for JSB's. I have BS4/FWB 300S and cannot get good results from either the 8.4gr or the 7.87gr JSB's...even 15-20yds look like a 2" wide shotgun pattern.
Soon as I go back to my trusty Meisterkugeln 8.2gr, it's doing ragged one hole groups again.

What was the accuracy difference in your gun when comparing the smaller sized JSB's? Was it a subtle difference or quite significant?

Well.....the JSB pellet measurements have been verifies as it pertains to how the Exacts fit the leade of my .177 R9 barrel. I just shot a few 5 shot groups upstairs at 18 yards using the variable head size (oval measurements) with 4.47mm max diameter, 4.50mm max diameter and 4.51mm max diameter and as suspected, at only 18 yards I couldn't detect any difference in group sizes except for the pellets with the variable 4.47mm max head size which did show an increase in group size relative to the other sorted sizes. Matter of fact, when loading pellets from the 4.47mm "V" tin I had a pellet fly from the leade when latching the barrel so I'm pretty sure that the two dry fires I had was due to loading pellets directly from my pellet pouch which were dumped directly from the old Exact lot tin.

Even when loading and shooting the "round" JSBs from the 4.49mm (there was only one 4.47mm pellet in the new tins), 4.52mm and 4.53mm sorted tins the accuracy was similar at only 18 yards with the 4.52mm lot shooting a bit tighter group. Looks like the distance will need to be stretched to at least 30 or 50 yards to determine any difference in grouping with my style of shooting. I do know that the fit in the leade was noticeably different between the different sorted sizes and also very consistent.

The fly in the ointment of all this is the prospect that all pellets in a tin will need measuring to weed out the 4.47mm size pellets even if all the other sizes are equally accurate.

By the way, I also shot a group at 18 yards with 5 left over CPLs that measured 4.54mm-4.55mm and noticed that I forgot how tight they fit the leade of my R9! Also, the group shot was the equal of the JSB Exact 4.52mm size pellets so I'll probably revert back to the CPLs and endure the washing/lubing rather than go through each 500 count Exact pellet tin measuring two points at 90 degrees to weed out the extra small pellets.

Anywhoo...here is a scan of the 18 yard target shot but I really wasn't shooting too good tonight from "bucket and sticks" so don't get too anal about the groupings. Basically the target shows that at only 18 yards all groups were similar except the group shot with the "oval" ("V") 4.47mm pellets.....
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Results are inconclusive at the short 18 yards and my rather inconsistent shooting when the target was shot. When the weather cooperates I'll do some testing at my 53 yard practice lane. Simply measuring the Exacts to weed out the undersized pellets is more of a chore than I'm wanting to do on a regular basis so adding another step will be avoided if possible. I'm planning to see if JSB Exact pellet size and "ovality" are actually a factor with MY "bucket and sticks" shooting style. LOL......I don't even have a shooting bench on my 53 yard practice lane so all shooting is done swayin' on a bucket which isn't very good for determining the "accuracy capability" of any of the equipment!

I do wonder how much difference an Exact being "out of round" or undersized actually makes at the target when shot by myself sitting on a bucket resting the gun on cross sticks, however the simple fact that I've had several 8.4 grain Exacts flip out of the leade when relatching my R9 barrel is enough to cause the unwelcome chore of measuring the things!

When I shot the CPLs the fit in the leade was very snug so it was easy to gage an ill fitter, or even determine if the pellet should be "pushed home" to be shot by visually checking how high the pellet sat in the leade. It's not so easy with the much less snug fitting JSBs because many fit so loose it's difficult (for me) to know when I have an undersized pellet when shot directly from the tin. I did however find that the pellets that actually measured 4.52mm-4.53mm were noticeably snugger fitting in the leade. Problem is that even with the "good 4 tins" there were only about 750 Exacts out of 2000 measured that were actually 4.52-4.53mm, all the rest were smaller.

In the past few years I've haven't had "fit in the leade" issues with the tight fitting CPLs. The half dozen or so undersized pellets from each box are easily weeded out when loading if they drop too deep in the leade. I'm also convinced that the relatively large CPL head size tends to "round out" any "ovality" simply by pushing them home before shooting. The issue I had with the last two cases I bought was simply the excess parting compound that necessitated washing and drying before lubing to minimize bore fouling with the R9. Well....as mentioned before....it's a lot easier to wash and lube a 1250 count box of CPLs than measure every pellet in a 500 count Exact tin to only end up tossing out a lot of those pricey pellets!

As a side note:
The case of CPLs I just ordered cost me $80.75 which included shipping for four 1250 count boxes after a 10% discount code which comes out to about 1.6 cents per pellet which isn't too bad and cheaper than the H&N FTTs at about 2 cents per pellet using the same "buy 4 and pay for 3 + 10% discount deal" before adding shipping charges..........but I digress! LOL 

[Kailua]

I was wondering if there was a consistent low weight difference in the smaller pellets?

[ancient1one]

Ed check out this video. He is shooting all JSB 18 grain pellets. After measuring and separating the pellets by head size he tests each size for accuracy.

[Pappy]

  When you close your eyes, do you see nothing but piles & piles of pellets & digital calipers???  LOL

 I admire your determination! had to be MIND NUMBING....

Isn't having a "Numb Mind" a prerequisite for entering this hobby ... and especially for staying into it!   

Pappy

[Yak54]

Ed

Could you describe your "method" for washing & lubing the CPL'S please ?

Dan

[Anylizer]

Isn't having a "Numb Mind" a prerequisite for entering this hobby ... and especially for staying into it!   

Pappy
[/quote]

  he says with glazed over eyes, & a deer in the headlights expression on his face!   

[nced]

Well....."I dooded it" and shot a 50 yard target to see if different JSB Exact pellet head sizes affected pellet accuracy!

Had a rainless but a bit breezy today so I took a target to my back yard practice lane and shot it hft style (sittin' on a bucket resting the gun on cross sticks). The target has a 7/8" diameter white center surrounded by a 1 5/8" diameter black bull. The black bull diameter is close to the size of a normal 50-55yard field target killzone so I thought it would be a good test. I did something a bit odd for me by zeroing the scope at 50 yards for this test rather than using my normal 30 yard zero and "holdover".

After zeroing using 4.52mm sized pellets shooting the middle "zero bull", 10 shots were taken at five additional bulls using pellets from the different sorted lots of JSBs. The "V" pellets (oval head pellets) were from the first tins Exacts I bought! I took two tins of "V"s (pellet heads oval by .02mm or more) and two tins of pellet heads that were either "round" or no more than .01mm oval.

The first bull shot after the initial zeroing was the one above the bottom right bull and I used 10 "round head" pellets measuring 4.52mm. Even though there was a bit of variable wind and the shooting was done from "bucket and sticks" I was disappointed by the group. The trigger pull weight was then reduced a bit and the group at the lower right was shot. Well....7 out of 10 shots went into the 7/8" diameter "white" with the other 3 strung horizontally into the "black" of the lower right bull. I felt that the group was good enough to use as a base for the other sorted pellet sizes so I used the same care, diligence and center of bull aiming point to shoot all other bulls.

Here's a scan of the target..........
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I'm pretty satisfied with the lower right grouping, however ALL the subsequent groups were rather mediocre! What surprised me was that both the "oval head" 4.48mm and the "round head" 4.48mm pellets grouped similarly at a mediocre 1 3/4"ish ctc, however the "oval head" 4.51mm pellets grouped a bit better at 1 1/2"ish ctc. The 10 shot group on the lower right bull was shot by "round head" 4.52mm pellets sorted from the 4 unopened tins bought later. The "oval head pellet groups" (the "V"s) were shot using pellets sorted from the first lot of JSBs bought.

Anywhoo....I'm convinced that shooting pellets directly from the "oval head pellet tins" was a major factor leading to a recent 13/60 ft score! LOL...I never considered that my "thought to be stellar" JSB Exacts could have grouped so poorly.....however the groups on the target scan tell a different story!

[Pappy]

Isn't having a "Numb Mind" a prerequisite for entering this hobby ... and especially for staying into it!   

Pappy

  he says with glazed over eyes, & a deer in the headlights expression on his face!   
[/quote

as he methodically weighs, sizes, cleans and lubes pellets, sipping Crown Royal from an empty AA 8.4 Diabolo field pellet tin ... reminiscing of the days when life used to have meaning.   

Pappy

[rokitman60]

I think it may be time for a new hobby!!!!!!!!

Although, when you're in competition, looking to beat out the other guy; I guess nothing seems excessive!  

[nced]

I think it may be time for a new hobby!!!!!!!!

Although, when you're in competition, looking to beat out the other guy; I guess nothing seems excessive!  

LOL.......for SOME this is part of the hobby! I do have to admit that I get almost as much enjoyment messin' with the R9 internals as I do shooting a match and this is also part of the hobby for me.

The issue with unevenly sized lots of pellets, i.e. pellet tins marked 4.52mm when there are none over 4.50mm is that such variations can affect how many targets that are knocked down during a FT match or how many squirrels are wounded on a squirrel hunt.

Funny thing is that when I used the 7.9 grain Crosman Premiers I didn't have very many "pellet size issues", only issues with the last case of CPLs being exceptionally "dirty" with excess parting compound which tended to foul my R9 bore more quickly.

Anywhoo.......I'm not about to give up on my airgun hobby due to such minutia as undersized or dirty pellets that may affect 50 yard accuracy because shooting my springer really is both fun and relaxing! Besides, shooting field target is more about IMPROVING MY SHOOTING than "beating the other guy". Hummmmmm.......I do admit that I get some satisfaction from using my break barrel R9 in piston class when the score ends up higher than some of the PCP class shooters!  I also have to admit that hitting only 13 out of 60 targets at a recent FT match was a bit of a bummer, especially since I didn't know that the pellets I was using grouped so poorly without sorting!

The only reason my brother and I started shooting field target a couple decades ago when living in West Virginia was to get in some off season target practice for the fall squirrel hunts and doing it with other airgunners and it's been a worthwhile journey ever since!

[ptpalpha]

I'm curious as to whether the H&N FTT's exhibit more consistency of head size and pellet weight.  Anyone know the answer?

[nced]

I'm curious as to whether the H&N FTT's exhibit more consistency of head size and pellet weight.  Anyone know the answer?

Well.... when I compared H&N FTTs from tins marked 4.50mm and tins marked 4.52mm I found that some in the 4.52mm tins were smaller than those from the 4.50mm tin and visa-versa! Matter of fact, I found the the pellet head variations for the FTTs was extreme at .005 (inch) difference between the smallest and the largest.....
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[ancient1one]

Ed you recently posted about weighing pellets. Did you check to see if lighter pellets had smaller head sizes and the heavier pellets larger head sizes?