Some interesting observations concerning pellet head sizes.

[StevenG]

There

Well by taking my digital caliper, and measuring ten pellets, ten times each, by simply turning the pellet a little everytime, I got 76 different measurements.

Have to say, that a digital caliper, isnīt a good tool to use for this job.

There is indeed a "technique" since lead is "compressible" and pellets indeed aren't PERFECTLY round, however I haven't found that pellet HEADS (not skirts) to be out of round so much that a good (if not perfect) representation of the size can be useful for presorting pellets for a more consistent fit in the leade.

I think you mean you can deform lead, that it is malleable. If you can indeed compress a solid with only your bare hands I am not shaking your hand. I would also ask that you be very careful, you could easily go squeezing the wrong material and end up with an atom bomb

[nervoustrigger]

For the purpose of distinguishing good size consistency versus poor consistency, calipers are perfectly adequate.  Achieving absolute precision to the fourth decimal place (ten-thousandth of an inch), not so much.

Having adjusted my analog caliper carefully, and checking it against precision gauge pins, I am comfortable interpolating head measurements to 0.0005".  Measurements are repeatable to perhaps 0.0002".  But really and truly, my interest in measuring has more to do with checking consistency within a given tin.  Those that are consistent don't always group well as you might imagine, but I have yet to get good groupings (sub-MoA at 43yds) from pellets that have a wide spread.  These measurements also appear to confirm what most airgunners have already found experimentally, which is that JSB and H&N tend to produce the most consistent pellets.  On the average, anyway.  Ed's results with the FTT are inconsistent with those I have received.  I don't go through very many H&N these days though so I don't have numbers from recent purchases. 

Many people swear by the boxed Crosman pellets which are made from a single die.  Oddly, the one time I purchased Crosman boxed pellets (die J .177 heavies), they had nearly the worst size spread of any I've measured.  Tediously sorting some matched pellets yielded excellent results but for me it was just too much effort to be worth it.

[K.O.]

Me I have drunk the head size matters coolaid and wish I could figure out a quick easy go/no go gage fore each barrel. Some are tighter than others of course.

A choked barrel of course is less sensitive to undersize and more so with oversize...

I have a tin of the 10.3g ultra mags that consistently measured  ~.1795-.179 shooting them thru my 1985 953 ( 500fps with7.9g) they were

as much as 35 fps slower out the barrel than the ultras that  came from a later tin that consistently measured ~ .178.

the harder lead made it more of a factor IMO...


Then on top of that there is the less engraved/more engraved part of it and the farther out you are trying to be accurate at the more it matters...




The JSB 10 grainers are better than the Crosman 10 grainers right... (could be a velocity thing but I don't think so)

[nced]

There

Well by taking my digital caliper, and measuring ten pellets, ten times each, by simply turning the pellet a little everytime, I got 76 different measurements.

Have to say, that a digital caliper, isnīt a good tool to use for this job.

There is indeed a "technique" since lead is "compressible" and pellets indeed aren't PERFECTLY round, however I haven't found that pellet HEADS (not skirts) to be out of round so much that a good (if not perfect) representation of the size can be useful for presorting pellets for a more consistent fit in the leade.

I think you mean you can deform lead, that it is malleable. If you can indeed compress a solid with only your bare hands I am not shaking your hand. I would also ask that you be very careful, you could easily go squeezing the wrong material and end up with an atom bomb

Yep........compress is a poor word choice!  if I'm referring to increasing the density of a solid or liquid! I'm actually using "compress" in the sense that the diameter of the lead pellet head can get compressed to a smaller dimension by the hardened stainless jaws of the caliper with pressure. I do  realize that this is deformation with the lead molecules getting "forged"  in directions opposite of the applied pressure.

Anuwhoo.......we do agree that a solid, or liquid isn't  compressible like a gas and I'm pretty sure that you're aware of my intended use of the term "compress"........sooooooo, we be splittin' semantic hairs (or rabbits) just for fun!   

[nced]

For the purpose of distinguishing good size consistency versus poor consistency, calipers are perfectly adequate.  Achieving absolute precision to the fourth decimal place (ten-thousandth of an inch), not so much.

Having adjusted my analog caliper carefully, and checking it against precision gauge pins, I am comfortable interpolating head measurements to 0.0005".  Measurements are repeatable to perhaps 0.0002".  But really and truly, my interest in measuring has more to do with checking consistency within a given tin.  Those that are consistent don't always group well as you might imagine, but I have yet to get good groupings (sub-MoA at 43yds) from pellets that have a wide spread.  These measurements also appear to confirm what most airgunners have already found experimentally, which is that JSB and H&N tend to produce the most consistent pellets.  On the average, anyway.  Ed's results with the FTT are inconsistent with those I have received.  I don't go through very many H&N these days though so I don't have numbers from recent purchases. 

Many people swear by the boxed Crosman pellets which are made from a single die.  Oddly, the one time I purchased Crosman boxed pellets (die J .177 heavies), they had nearly the worst size spread of any I've measured.  Tediously sorting some matched pellets yielded excellent results but for me it was just too much effort to be worth it.

Guess it all depends on the individual gun. Years ago I home chopped and choked a .177 R1 barrel for use with my R9 and it was the ONLY HW springer I've owned that shot the Beeman FTS (rebadged H&N FTT) well. Here is a scan of a target shot years ago hunter class field target style (sitting on a bucket resting the gun on cross sticks) at 50 yards where the first group was about 1/2" ctc. Then I actually zero'd the scope to be "dead on" at 50 ayrds and then I shot the second 5 shot group in which all 5 FTSs went inside a 1/2" circle........
Uploaded at Snapagogo.com

Here is another target scan where I was using a different .177 R9 and compared the accuracy of the Beeman FTS vs the CPL from the die lot marked and dated box..........
Uploaded at Snapagogo.com

Anywhoo......whatever works best in your gun is the one to use for sure! Years ago I bought 3 Cummins Truckload Sale Chinese B3s and cobbled them together into a pretty good shooter with JSB EXACTs , however that gun shot CPLs into patterns instead of groups....go figgure. Here's a scan of a 25 yard target shot hft style using Exacts........
Uploaded at Snapagogo.com

Currently my .177 R9 shoots the 4.52mm 8.4 grain JSB Exacts very accurately, however my current R9 is the only one I've owned that shot the Exacts as accurately (or better) than the die lot marked and dated CPL..........5 shots into 5/8" ctc with 4 out of 5 within 3/8" ctc..........
Uploaded at Snapagogo.com

[gandalfretlaw]

I did a double blind test with my rifle using caliper sized crossman pellets. There was a definite trend. Just tight enough was perfect although very tight was pretty good too. If I remember right I shot two groups with each pellet size. All the pellets were in ziplock bags that were randomized with a piece of paper inside folded in half with the size. It wasn't perfect as with a break barrel you can tell loose and tight but it was pretty good.

I think I took sorted pellets and put like 20 in a bag and put the size on a piece of paper and folded it in half. Then I randomized the bags and marked them 1,2,3,... with a sharpie. Then I went through and recorded the bag number and shot a group for each bag in order. I then repeated through the bags. At the end I put them in a spreadsheet and reordered the information into head size. The groups did correspond, too loose and the groups were big, just right 4.48 in my case and they were great and then poor as they got larger. I think some very large ones 4.56 or so also shot well. The graduations weren't very exact but more of a range, so 4.47-4.49 in my case really shot pretty well.

I've since noticed that manufactures tend to offer loose (~4.48) and tight (~4.52) size pellets, at least RWS does. Gammo pellets always measure around 4.45 and are way loose.

[Ken T]

Pellets are easily measured with either calipers or micrometer.It simply requires quality calipers or micrometer.The cheap ones won't cut it.Cheap calipers usually take a fair amount of force to move and are not good for precise measurements.I use Mitutoyo,Starett,and Brown&Sharpe measuring tools.It is necessary to develop a light touch using measuring tools.Try measuring a gauge block or the shank of a drill bit to check repeatability of the calipers.
I've seen QC inspectors get a usable measurement off of soft rubber molding compounds using calipers.

[Rolling Thunder]

Walter the blinding you did is a very good way to reduce psychological factors on accuracy!

Your test would lend itself to statistical analysis.  Remember that 4 random sets of identical pellets would be expected to produce different groups, even by chance.  The way to check this is by testing the grouping differences for statistical significance (essentially a test that determines whether what happened could have been by chance).

If your groups are well centered on the bull, you could measure the radii from centers of POI to bull center for each group.  If you have this data and are interested, I could run some stats on it.

Kim

PS you'd need >10 shots per bull to test properly, or shooting several bulls with the same pellet set (say) 5 shots each

[gandalfretlaw]

here's the link
http://www.gatewaytoairguns.org/GTA/index.php?topic=35139.msg326815#msg326815

http://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=35139.0;attach=46655

[Rolling Thunder]

Thanks Walter.  Not sure about your notation:  Are the measurements group diameters?  What is group 1 and group 2, and elevation?

Your link says 20 targets / 5 shots each.  Do you have that data?

Also can you PM me the excel file ?

[AudiS4]

There

Well by taking my digital caliper, and measuring ten pellets, ten times each, by simply turning the pellet a little everytime, I got 76 different measurements.

Have to say, that a digital caliper, isnīt a good tool to use for this job.

There is indeed a "technique" since lead is "compressible" and pellets indeed aren't PERFECTLY round, however I haven't found that pellet HEADS (not skirts) to be out of round so much that a good (if not perfect) representation of the size can be useful for presorting pellets for a more consistent fit in the leade.

I think you mean you can deform lead, that it is malleable. If you can indeed compress a solid with only your bare hands I am not shaking your hand. I would also ask that you be very careful, you could easily go squeezing the wrong material and end up with an atom bomb

Yep........compress is a poor word choice!  if I'm referring to increasing the density of a solid or liquid! I'm actually using "compress" in the sense that the diameter of the lead pellet head can get compressed to a smaller dimension by the hardened stainless jaws of the caliper with pressure. I do  realize that this is deformation with the lead molecules getting "forged"  in directions opposite of the applied pressure.

Anuwhoo.......we do agree that a solid, or liquid isn't  compressible like a gas and I'm pretty sure that you're aware of my intended use of the term "compress"........sooooooo, we be splittin' semantic hairs (or rabbits) just for fun!   

Well this is precisely my point. You need to measure a pellet head on at least three different places, and then take the mean of those measurements, since they arenīt completely round. Otherwise there is to much error readings to make it statistically accurate.

[nced]

"Well this is precisely my point. You need to measure a pellet head on at least three different places, and then take the mean of those measurements, since they arenīt completely round. Otherwise there is to much error readings to make it statistically accurate. "

Hummm....I could care less about "statistically accurate measurements" since no more precise sorting was needed to achieve a consistent fit BY FEEL ! Anywhoo......rather than "measure a pellet head on at least three different places, and then take the mean of those measurements" to prove what I already know......I'll simply shoot the brand of pellet that DOESN'T need sorting to shoot accurately!

[StevenG]

Simply using presorted pellets is likely better for you, but far less interesting to discuss

Which is I am sure what JSB does and all pellet makers to one degree or another. Some simply sort to a better degree.

[mista meener]

Interesting about the posted fine accuracy folks are getting with H&N FTTs because they didn't work too well in my R9! The pellet fit in the leade was REALLY VARIABLE so I spent a week actually measuring the heads of 2500 H&N FTTs (4 tins marked 4.52mm and one tin marked 4.50mm).

While the pellets from the 4.50mm tin were pretty consistent, the ones from the 4.52mm tins....not so much. Matter of fact, there were some in the 4.50mm tin that were larger than some in the 4.52mm tin, and some in the 4.52mm tin that were smaller than those in the 4.50mm tin. Kinda made me wonder why they even  TRIED to sort by size. Anywhoo.....after sorting the pellets by size the separated lots did fit my R9 leade consistently and each sorted lot was even rather accurate! LOL....WAY too much hassle for me to sort out tins of FTTs so I tried the 4.52mm 8.4 grain JSB Exacts and I had a good replacement for the die lot marked and dated 7.9 grain Crosman Premiers. While the cases of CPLs I've bought for the last few years have been consistently accurate, the last two cases I bought also contained excess parting compound on the pellets which blackened my loading fingers and crudded up the R9 bore faster than I liked. The "dusty CPLs" caused me to go through the hassles of washing and drying the CPs before lubing for use. Another "issue" I've had with the hard lead CPs from "day one" was the fact that when unlubed they would foul the bore rather quickly, then it was a bear to strip out the "soldered (or so it seemed) fouling" since the pulled patches only polished the packed lead.

Here are a couple pics of the sorted H&N FTTs spoken of......
Uploaded at Snapagogo.com
Uploaded at Snapagogo.com

Here is the method I used for measuring......
Uploaded at Snapagogo.com
The pellet was always on the same position on the Formica desk top, the pellet was always measured in the same position on the calliper jaws, only enough pressure was applied to just lift the pellet from the surface when measuring. Not real "scientific", however the sorted pellets consistently fitting the R9 leade within each lot did verify that the sorting method was at least useful.
Uploaded at Snapagogo.com


While I don't put much "faith" in the "4th decimal" using a digital caliper for the measuring, the heads of .177 cal pellets did vary .005 from smallest to largest which is well within the accuracy limits of my caliper. Matter of fact, even the more consistent 4.50mm tin of pellets had a head size variation of .002! Just for grins I pulled out 10 CPLs from the box and randomly measured the heads.....ALL  but two read exactly .177 on the digital caliper with the other two reading .1765! Again, I don't put much faith in the "4th decimal" but it did show that the CPL heads were much more dimensionally consistent!

Anywhoo......I found the accuracy of the 8.4 grain JSB exacts are the equal of the CPLs from my R9, I don't need to wash or lube them so I've used Exacts since last year!  Just for grinns I pulled a half dozen 4.52mm JSB Exacts from my pellet pouch and these are the readings I got (again, I'd take the 4th decimal with a grain (or shaker) of salt.........
.1765  .1770  .1765  .1765 .1765  .1765
Funny thing is that my current R9 is the only one of about a dozen that I've owned that shoots the Exacts as accurately as the CPL!

you must have a lot of time on your hands to tackle a project like this. shooting for me is to relax you have what seems like a stressful job lol. I hope you enjoy yourself because I could not doing that

[Racer X]

I tried to measure the pellets. I tried a micrometer and could put small dents on the pellets so that was no good. I tried calipers and had better luck but not real results. I watched Teds holdover video.



This looks like a great way to measure consistently.

[michaelthomas]

I'll throw my 2 cents in here and assure everyone it will be worth every penny.

I pretty much do nothing but shoot competitive air rifle benchrest.  I do not know of a more particular bunch of guys.

I used to sort pellets by various methods.....rolling, optical comparator, and laser micrometer.  The last two methods were accurate to .0001 and beyond.  The first thing you notice with the laser mic or the 100x comparator is that there is no such thing as a truly round pellet.  About the best you can hope for with a tin of JSB's is .01mm out of round....with most being worse.  When taking roll sized pellets and double checking them on the laser mic.....I found that the out of round really screwed with the results that were being obtained.  For those that roll pellets.....simply squashing the skirt very slightly will make the pellet roll to a completely different place.  The circumference will stay the same.....but it rolls different.  I always pushed my pellets through a die to size the skirts consistently prior to rolling to combat this, but it really didn't work according to the laser mic or the comparator.

Long story short on rolling......the pellets that were classified by rolling were not actually the size graduations that I thought.  I tested them in their respective group sizes....and always seemed to find a particular group that shot the best.  I have no real explanation for that.  I quit rolling pellets when my friend beat me 2 matches in a row with pellets out of the tin.  He was too lazy to sort, and refused to do it. 

I then advanced to using the 100x comparator or the laser mic to take 2 position averages 90 degrees apart.  Still very time consuming.  I shot every sort size range individually and kept track of the results.  Then one day, I took the smallest pellets and combined them with the largest from the sort and shot some cards with those.  So these were the all the pellets that were grossly different than the majority on both ends of the scale.  Strangely enough.....I shot just as well over a 3 card average compared to any other size group I tried.

The sorting phase in my shooting history has been a lot more complicated than I care to write.....it would take a book to get it all down.  I have gone from ignorance to staunch belief to indifference over my time shooting benchrest.

I can give one particular case that casts great doubt on the entire head sorting thing for me.  I have a particular lot of JSB 8.44's that shoot averages of 250 18-20x indoors with an average head size of .1782".  They are fantastic pellets that would lead someone to the conclusion that my barrels like larger head sizes of 4.53 or so.  I also have another batch of JSB 8.44's that average exactly the same scores, but are .1770 in average head size.  I also have tons of other batches that are the same head sizes as these I mentioned......and every other size you can think of that come no where near the performance of the other two.  How does that compute if head size is what matters?

The above example tells me that head size may matter.....but it's certainly not the only thing that matters....and maybe its not nearly as significant as we thought.

I can also tell you that I have weighed pellets til the cows came home.....and could not find any conclusive evidence that weight sorted pellets improved my scores at all.  It should be noted that I only shoot JSB's or AA pellets.  Maybe weighing is beneficial for the more widely varying pellets like the crosmans. 

I quit sorting pellets completely last winter, and so have the other guys that shoot my bench rifles.....and still somehow we have managed to set 14 new national benchrest records in the past year.  All with pellets straight out of the tin. 

I have 55 yards indoors where I can shoot off a dedicated bench and a machine rest with a rifle that is extremely consistent.  Without those things, I think it would have been very, very difficult to arrive at the conclusion that I have. 

Right now.....I buy a tin of every batch of a particular pellet I can find.  I shoot a few cards with each one indoors.  If I find a great shooting tin, I order all I can of that particular lot.  That is the extent of my sorting these days. 

This has drastically simplified my shooting life.....but has not yet changed my performance.

Please know that I am in no way knocking anyone that finds benefit to pellet sorting.  If it works for them.....there is no reason to quit doing it.  I'm just sharing my personal experience in the matter.

Mike

[Rolling Thunder]

QED

[nervoustrigger]

Great stuff as always, Michael.  Thanks for sharing your hard-earned experience.  That was easily worth a quarter, maybe even a shiny silver dollar!

And while I don't normally think of myself as a lazy person, I lack the vigor that Ed has applied to sorting his FTTs.  For the purposes of my pellet log, I just measure 10 random samples from each new tin of pellets, 2 places each (20 readings), for the purposes of establishing whether the heads are quite consistent or have a lot of variation.  I have not found any evidence that a particular barrel prefers a certain head size when applying that across different makes and types of pellets.  But for a given brand and type of pellet, I am totally convinced that there is a negative impact on groupings when head size varies a lot within the tin.  The link Kirby posted by Wingman NZ seems to support that argument.

I seldom see more than about 0.001" to 0.0015" spread in a tin of JSB or Air Arms pellets, so seeing as how that is mostly what you guys are using, I surmise that is why you don't see much correlation between head size and groupings.  When I sort pellets from a tin having a spread of 0.003" or more, the difference is pretty compelling.

And as good as JSB seems to be at producing consistency within a tin, I find big differences in the groupings I get with a tin bought a year ago versus six months ago versus last week.  You have written of variations in head and skirt geometries that you found between batches using the optical comparator so I'm preaching to the choir here.

Lastly, I freely admit that I lack both the patience and the equipment to sort pellets to the degree you have, so it relieves me greatly to find that you and other experienced airgunners have arrived at the same conclusion I did, though with considerably more effort.  And that is to buy pellets from a proven quality manufacturer, test them, and when you find a stellar performing tin, go back and buy as many as you can justify.

[K.O.]

Thanks for the input Michael

Me at this time I shoot mainly 20-35 yards and not benched it is more like field conditions (sitting, prone, kneeling, side rested and not etc) so I would have to change that because I feel I am the biggest variable.

I basically like to shoot how I would hunt...

But still all the little things add up especially as you are trying to reach out further...

and benchers can teach us a lot  about different barrels and barrel prep consistent shot cycle and such... heck two groove, three groove, poly, taper lapped, choked, tight rimfire, slow twist, smooth twist, and on and on and on...
http://benchrest.com/archive/index.php/t-83260.html


Each barrel is an individual and will like best what it likes best as far as head size and velocity/weight combinations...

at 30-35 yards with CPL or CPUM looking for .5 groups for hunting well not as critical but at 50 to 60 yards I feel if I can sort to get JSB consistency with CPUMs I do feel it could help be more accurate with them.

Me I am coming at this from the view point of trying to get the best out of  $20 Crosman 1:16 twist , $40 Daisy 1:15 twist and $40 L.W. 1:17.7  .177 Barrels... low budget performance... and having fun trying... so if I am wrong no biggy...

Heck I have just cut a very short portion of a Crosman barrel to use to play with indexing those three barrels in an effort to make sure that I put the port in the best position... we will see how that goes..

like this but no o-rings because it is just to find the best position to drill the port.

http://www.gatewaytoairguns.org/GTA/index.php?topic=37036.0



For those that have no Idea what I am talking about...

http://www.gatewaytoairguns.org/GTA/index.php?topic=52432.0


the effect of rotating the barrel

http://www.network54.com/Forum/79537/thread/1394256650/Barrel+rotation+-+indexing+and+possible+effect+on+POI+of+different+pellets.

http://www.gatewaytoairguns.org/GTA/index.php?topic=82972.0


Now combine that with floppy 7/16 barrels (harmonics) and the velocity differences and such and I feel it shows that on a non benchrest rifle

it(pellet head size) just might make more of a difference...

I think that we have a lot we can learn from the bench rest crowd even if we are not shooting  $200-$700 barrels but it does take thinking about the differences...

So I do think you have to think about each individual rifle and it is just one of many variables...

[nced]

I lack the vigor that Ed has applied to sorting his FTTs.

ME TOO! That was a "one shot deal' and I was verifying what I felt with the FTTs fit in the leade and I wondered if it was a "one tin affair" or if all tins of the lot I bought were similar......and indeed, all tins had a large variation on pellet head sizes regardless of wht size was marked on the tin!

When shooting CPLs or JSB Exacts all I need to do was grab a pellet out of the pellet pouch that was dumped straight from the box or tin without sorting!