Should I sort pellets by weight or head size? Or both?

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Paio

Paio

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Apr 20, 2015
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Minas Gerais, Brazil
I sort pellets before shooting to check for damaged skirts or heads. Now I want to go a step further. I have been reading a lot about weighting and head diameters. I use Smooth Twist barrel. Should I sort by weight or head diameter? What is the best sorting process for accuracy? 

I have been delaying this for quite sometime (I am a perfectionist and I am scare of starting this time consuming process which may take some fun from me...) but if I want to tight my groups I see no other way. 
 
Sorting pellets can be tedious, and many say it is unnecessary. I would recommend that you have a way to do it, and that it will pay off at some point.
The electronic gages that can weigh to 0.1 grain are amazingly inexpensive. Having one of these available is a quick way to know if you have irregularity. I have had reports of pellets mixed in tins, and checking a few for weight variance is useful.

I believe head size is more critical than weight. It affects the POI, and variance is hard to detect. In most cases, when you buy quality pellets, you can expect only small variance in diameter. But first, I say that you need to identify by measurement what diameter is best for a given barrel and its choke/rifling. Many say that you should simply get different pellets, and keep trying those until one is shown to group better. Talk about tedious. But if you do so, do you know what exact diameter that "liked" pellet was? 

Identifying a good fit for your gun, and then being able to assure that other pellets (even the same brand) is the same size has some true value - as a fundamental. One approach some shooters use is to slug several pellets, and gage the OD of the pellet to see the inside diameter of rifling grooves. Using a pellet very slightly under that diameter is usually a good start. Most of the time, you'll find a variance of about 0.01 mm within a tin - but I have seen much more. At variances of 0.02 or more, you can see a difference in the POI.

Now, if you are going to shoot in competition, it can very well be worth the effort (really, just a few minutes) to sort the 60 or 80 pellets you would need, and be sure that every one of them is within 0.01 mm of nominal. In a case when one flyer could be significant, the effort is not much. Variances do occur within the same tin, and even more often, between lots. I have had several customers feed back that knowing that they had received a "bad" tin of pellets save them from making scope adjustments or other trials that wouldn't have worked, anyway. Unfortunately, manufacturers still seem to lose some process control, and have even stopped labelling the tins by size. 

Just the "psychology" of knowing that variable is controlled can help a shooter. I remember this quotation, from a physics teacher long ago:

"In physical science the first essential step in the direction of learning any subject is to find principles of numerical reckoning and practicable methods for measuring some quality connected with it. I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science, whatever the matter may be." Lord Kelvin [PLA, vol. 1, "Electrical Units of Measurement", 1883-05-03]

 
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Sorting or even resizing for head size IME has the greatest impact on how consistent your POI will be.

Weighing, well that will really depend on the percentage of variance you are seeing in your preferred pellets. So for example lets say you are shooting 50gr 30cal pellets and you weigh out a tin and see a range of 49.0gr to 49.5gr, well your variance is only ~1% of the total weight. IME with 30cal at 100y/m a 0.5gr difference in weight makes little/no noticeable difference in POI. I start seeing a difference above 1gr in 30cal.

But in my 0.177 the percentage of variance is always greater. So I will typically have a spread like 15.5gr to 16.8gr on JSB 16.2gr pellets. I absolutely do see a change in POI at 25m and 50y with these differences. So I sort them into group by 0.2gr, e.g. 15.5gr to 15.7gr.

As for measuring head size the most accurate way is to air gauge them, costs around $350 plus the equipment needed to use the air gauge (compressor, reloading press). The way I do it is to use the new sponsors pelletgage. It's a "go/no go" gauge. Last and cheapest is rolling them (Google is your friend). For resizing NOE dies and tBt resizer.

Dig around here, lots of information.
 
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The more imperfections you sort out, the more consistent your ammo will be, which should give your rifle the best chances at being as accurate as it possibly can. 

Weigh, size, roll... whatever your method. I would start with whatever will remove the highest quantity of "imperfect" pellets first. Then move on to the next step that will remove the most imperfections. 
Whenever you can, use one procedure to help with the next procedure. For example, I use a speedy pellet inspector. The by product is a mass of pellets all facing the same direction. So, I use that system to gently place them heads up on a flat surface. This positioning makes it much easier for me to grab them for weighing. 
I'm also working on a series of vids in my spare time going over all the different methods and if they show a substantial improvement. 
Tom
 
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Joe Peacock and I have discussed the inspection using Speedy Pellet Inspector. I think what is most important is any flash or irregularity on the pellet skirt or head that could affect the concentricity of the pellet. You can rub the base of the skirt on some rough paper to remove it. The concept is that any imperfection (and this might not be visible) that would affect the rotational moment of the pellet is adverse. It needs to spin cleanly and in a balanced manner exiting the rifled barrel in order to have good ballistics. Incidentally, Joe manufactures the plastic parts of Pelletgage, and is a great guy to know! He came out to a field target match at the Yegua Club, and won the first time he shot with us. I believe he is a competitive benchrest shooter now.
 
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The biggest problem I have is that I still get flyers despite having visually inspected, weighed and sized the pellet. I don't get enough to significantly effect me, but it's the difference between a 250 and a 24x score.

To add confusion to the situation I have fired pellets that I have rejected do so some imperfection as a test only to have them fly true. As an example I see JSB/FX pellets from time to time that have for lack of a better description an black line across the top of the head. Obviously something is abnormal with them, yet they fire true. I get ones with marks inside the skirt that will fire true as well. Ones with cuts/lines across the bottom of the skirt I smooth on a sheet of paper.

So I'm a little lost as to exactly what makes a pellet a reject or a "perfect" specimen. Any input is welcome!

So short of inventing a spin balancer to put every pellet through, is there something we can do to find those with off center masses?
 
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"Percula"The biggest problem I have is that I still get flyers ...
So I'm a little lost as to exactly what makes a pellet a reject or a "perfect" specimen. Any input is welcome!

So short of inventing a spin balancer to put every pellet through, is there something we can do to find those with off center masses?
Click to expand...
Not sure of the answer, but I do think that the rotational stability is a factor that is very difficult to cull out. Close examination of the entire pellet with a 10x loupe and comparison to other know good examples (perhaps even from a previous lot that you kept a "known good" from) might give you some concept. Nuances like surface condition might even be a factor. Anyway, look very closely.
 
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"Pelletgage"Sorting pellets can be tedious, and many say it is unnecessary. I would recommend that you have a way to do it, and that it will pay off at some point.
The electronic gages that can weigh to 0.1 grain are amazingly inexpensive. Having one of these available is a quick way to know if you have irregularity. I have had reports of pellets mixed in tins, and checking a few for weight variance is useful.

I believe head size is more critical than weight. It affects the POI, and variance is hard to detect. In most cases, when you buy quality pellets, you can expect only small variance in diameter. But first, I say that you need to identify by measurement what diameter is best for a given barrel and its choke/rifling. Many say that you should simply get different pellets, and keep trying those until one is shown to group better. Talk about tedious. But if you do so, do you know what exact diameter that "liked" pellet was? 

Identifying a good fit for your gun, and then being able to assure that other pellets (even the same brand) is the same size has some true value - as a fundamental. One approach some shooters use is to slug several pellets, and gage the OD of the pellet to see the inside diameter of rifling grooves. Using a pellet very slightly under that diameter is usually a good start. Most of the time, you'll find a variance of about 0.01 mm within a tin - but I have seen much more. At variances of 0.02 or more, you can see a difference in the POI.

Now, if you are going to shoot in competition, it can very well be worth the effort (really, just a few minutes) to sort the 60 or 80 pellets you would need, and be sure that every one of them is within 0.01 mm of nominal. In a case when one flyer could be significant, the effort is not much. Variances do occur within the same tin, and even more often, between lots. I have had several customers feed back that knowing that they had received a "bad" tin of pellets save them from making scope adjustments or other trials that wouldn't have worked, anyway. Unfortunately, manufacturers still seem to lose some process control, and have even stopped labelling the tins by size. 

Just the "psychology" of knowing that variable is controlled can help a shooter. I remember this quotation, from a physics teacher long ago:

"In physical science the first essential step in the direction of learning any subject is to find principles of numerical reckoning and practicable methods for measuring some quality connected with it. I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science, whatever the matter may be." Lord Kelvin [PLA, vol. 1, "Electrical Units of Measurement", 1883-05-03]

Click to expand...
Thanks for the detailed information and considerations. Following your advice on what your believe affects the POI, I just ordered two pellegages .22 and .25. 
 
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"Tominco"The more imperfections you sort out, the more consistent your ammo will be, which should give your rifle the best chances at being as accurate as it possibly can. 

Weigh, size, roll... whatever your method. I would start with whatever will remove the highest quantity of "imperfect" pellets first. Then move on to the next step that will remove the most imperfections. 
Whenever you can, use one procedure to help with the next procedure. For example, I use a speedy pellet inspector. The by product is a mass of pellets all facing the same direction. So, I use that system to gently place them heads up on a flat surface. This positioning makes it much easier for me to grab them for weighing. 
I'm also working on a series of vids in my spare time going over all the different methods and if they show a substantial improvement. 
Tom
Click to expand...
Thanks for your input. I have the speedy pellet inspector and it helps a lot. I am going first to size sorting and will see the results in my gun. 
 
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"Percula"Sorting or even resizing for head size IME has the greatest impact on how consistent your POI will be.

Weighing, well that will really depend on the percentage of variance you are seeing in your preferred pellets. So for example lets say you are shooting 50gr 30cal pellets and you weigh out a tin and see a range of 49.0gr to 49.5gr, well your variance is only ~1% of the total weight. IME with 30cal at 100y/m a 0.5gr difference in weight makes little/no noticeable difference in POI. I start seeing a difference above 1gr in 30cal.

But in my 0.177 the percentage of variance is always greater. So I will typically have a spread like 15.5gr to 16.8gr on JSB 16.2gr pellets. I absolutely do see a change in POI at 25m and 50y with these differences. So I sort them into group by 0.2gr, e.g. 15.5gr to 15.7gr.

As for measuring head size the most accurate way is to air gauge them, costs around $350 plus the equipment needed to use the air gauge (compressor, reloading press). The way I do it is to use the new sponsors pelletgage. It's a "go/no go" gauge. Last and cheapest is rolling them (Google is your friend). For resizing NOE dies and tBt resizer.

Dig around here, lots of information.
Click to expand...
I didn't know the Yrrah rolling method. I just did a device and started the process. Also I ordered the pelletgages and a scale. Anxious to shoot and see the initial results after sorting them visually and rolling. Thanks for your considerations. My rolling device here:
 
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I would like to weigh ( pun intended! ) in here, this topic is of great interest to me. I have just started to educate myself in sorting pellets, 1st by weight, 2nd by head dia., 3rd by skirt deformation, and lastly by overall inspection of pellet looking mainly for deformation or oddities in pellets etc. from what I'm finding head dia. or any imperfections in the head of the pellet seem to make the most difference at the target (namely flyers!) just so you know I'm shooting indoors @17yds., wish I could get @ least 25yds! needless to say my testing has shown that head dia.(finding the dia. your barrel likes) and any imperfections in the head of the pellet have the largest effect on accuracy down range, I know concentricity plays a vital role in all this but have no way of actually measuring this ( I think the YRRAH method is probably best ), Now I know what a lot of people are thinking right now?, what about weight? well that does make a difference especially @ greater distances, but not so much in the unpredictable flyers that seem to defy logic! If I get one or two pellets out of 25 that go low but are consistent, than ok they probably weigh more or I missed them when weighing etc. I know there is so much more that I need to learn ( like eliminating canted pellets in the the chamber etc.) right now I'm focusing on concentricity & eccentricity?
 
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Gentlemen:

These are some procedures and actions I have done so far, some weighs, a lot of questions and doubts on the pellet sorting. I encourage anyone to jump here and provide their inputs and experiences:

1 - I took four tins of .22 JSB Exact Heavy 18.13 grains and rolled them using the Yrrah method. It was amazing to see how the pellets in the same tin roll in different curvatures/radius. Consequently different pellet diameters - assuming they all have the same skirt diameters. Some pellets describe a so strange curvature that I imagine they are off center and potentially they are all fliers. I am happy to get rid of them.

2 - I badly want to resize all pellets skirts to single diameter to improve the rolling method accuracy and I couldn't find anything which I really trust. What I found are pellets head sizers (like this one well made here: http://www.airrifletuning.com/products/tbt-pellet-sizers/). These ones will resize the head and skirts to a same diameter which it does not make any sense for me. Please correct me if I am wrong here. Does anyone know any device that resizes the pellet head and skirts simultaneously in different diameters?

2.1 - I also tried to find the original JSB pellet dimensions (I am focused on JSB 18.13 grains .22). I didn't find anything here on the forum or Google. I emailed JSB but no answer yet. I want to know the original skirt diameter and there is no way I can measure without squeezing and consequently damaging the skirt.

3 - I ordered some pelletgages for different calibers. As soon as they arrive I will be able to separate the pellets by head diameter. I also ordered a scale but I will move to weighting them after I am comfortable with my pellets heads and skirts measurement/calibration process and field tests.

4 - I am concentrating in studying the pellet sorting process specifically for my FX Wildcat so far. ST barrels have no grooves such as a conventional barrel which I could insert a slug and try to measure the head and skirt. Also the ST is choked so I am lost on how would be "scientifically" the method to determine the proper pellet head and skirt diameter. It seems there is no other way other than sort the pellets by diameters & weights and test them all in the range. This is quite frustrating. 

5 - Talking on weights I have no idea what would be an accepted weight tolerances. If 0.5 grains or 0.8 or 1 grain, etc, between pellets. Again it seems field test is mandatory. 

6 - After reading all the inputs on this post (and certainly respecting your experience and time spent to write which I really thank you) I am still confused on what really improves the accuracy and tightens the groups (in order of priority and assuming all pellets are free of head and skirt damages):

A) Head diameter?
B) Skirt diameter?
C) Weight?

What is really the most important and the one I should concentrate my efforts and time?

7 - During all this inspection and sorting process I opened the tins, exposed pellets to air, I handled pellets with my fingers and sure some oxidation will occur. Do you guys are concerned with this or not? Or am I overly concerned? 

8 - I visited JSB internet site and noticed they have premium pellets on .177 calibers ("individually selected pellets only from the best manufacturing batches" and certainly for competition). I wonder why not they don't have for other formats and calibers. Certainly there is a market for that.

9 - After handling, sorting and preparing my pellets I would like to put them in a air tight container and not back on the tin. I believe this will prevent oxidation. I found Pellcan but they don't manufacture it any more. Does anyone have any other container being used these days? Any tips on how to proper storage them after opening the tins?

Well, this is an extensive subject. I have countless of additional questions and doubts popping on my head, such as why all the JSB pellets head diameters (from 5.5 to 5.53mm) have apparently the same skirt diameter? How Ted put 96 pellets in the same hole without a single flier (I know the gun has different set ups but 96 shots without fliers is a lot...), etc, etc, etc.

Last but not least, I also do plinking and hunting. For these I only sort pellets by visual inspection. My quest in sorting pellets in a more technical way are for long distances shots such as 100m and above at my range. I just want to tighten my groups and be a better airgun shooter. Thanks. 
 
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I shoot Field Target, and sometimes Bench Rest. First i weigh my pellets in .03 grain divisions. So my latest batch of AA 8.4 Diaboblo Fields were from 8.32-8.52grs. I sorted them 8.32-8.34, 8.35-8.37 and so on. The I head size each weight with the pelletguage. I've yet to roll test afterwards but that would be the next step. No need to inspect skirts because with rolling you are checking for out of round in both the heads and skirts.

As for different size skirts i wouldn't worry about it too much as the blast of air upon firing with size the skirt to the barrel of the gun.
 
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I agree john, the air pressure sizes the skirt to bore Dia., I use the roll method to help identify out of round heads or imperfections in the head and or skirt, will say this I've purposefully bent or put nicks in skirts to see what effect it had on the groups, quite honestly it made little to no difference at the target! But it does have an effect when u damage the heads ( on purpose! ) don't take my word on this,try it for yourself!
 
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"Paio"

2 - I badly want to resize all pellets skirts to single diameter to improve the rolling method accuracy and I couldn't find anything which I really trust. What I found are pellets head sizers (like this one well made here: http://www.airrifletuning.com/products/tbt-pellet-sizers/). These ones will resize the head and skirts to a same diameter which it does not make any sense for me. Please correct me if I am wrong here. Does anyone know any device that resizes the pellet head and skirts simultaneously in different diameters?


Click to expand...
http://www.trrobb.com/product/adjustable%20pellet%20sizer%20177 This one leaves the skirt intact and may even straighten it a bit.
 
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I have always weighed pellets for competition but mainly this is to weed out the extremes - worst I have found were an 8.00gr pellet in a tin claiming to be 8.44gr and at the other end some over 8.80gr at the same "published weight". My conclusion over the years has been that as far as weight is concerned, in all but the very extreme ranges of the gun's capability 2 or 3 10ths of a grain of wieght variation is not a significant amount (may not apply to benchrest, I've never done that seriously) - and YET I still weigh my pellets! As someone mentioned above, the psychological - top 2 inches - aspect of shooting is not to be underestimated.

Ok now the thing I think is more significant, but have only just started experimenting with due to getting a PCP that isn't as accurate as it should be but with nothing "wrong" with it, is: HEAD SIZE...

Just got a Pelletgage, what a neat product it is, and started measuring various pellet types that I had around, I was shocked:
(worth noting that the pelletgage takes a bit of experimenting to get an accurate way of measuring and I have checked my method against calipers)

JSB 16gr with a published size of 5.51mm: 30% 5.53mm, 60% 5.54mm, 10% 5.55mm
JSB 16gr with a published size of 5.52mm: 80% 5.52mm, 20% 5.53mm
JSB 18gr with a published size of 5.52mm: 25% 5.55mm, 60% 5.56mm, 15% 5.57mm
H&N Baracuda Match published head size 5.51mm: 40% 5.53mm, 60% 5.54mm
Air Arms Field 18gr (rebranded JSB) size 5.52mm:40% 5.55mm, 60% 5.56mm

Of course the only thing that matters is what effect all this has on consistency out of the gun. I hoped that regardless of the actual size, at least once they were sorted into size groups they should be consistent albeit with different POI... unfortunately not.

Single 5 shot groups are deceptive, (which this experiment also demonstrates) so I shot 5 x 5 shot groups for each head size and took an average c to c of all five. 

(50 yards)
JSB 16gr 5.52 12mm
JSB 16gr 5.53 17mm
JSB 16gr 5.54 18mm
JSB 18gr 5.55 18mm
JSB 18gr 5.56 20mm
JSB 18gr 5.57 22mm
H&N Baracuda - groups too large to bother

Thing to note: in each 5 group set, up to 5.55mm, at least one group was 1/2" or less which shows how deceptive taking a single 5 shot group can be as a measure of a gun's accuracy.

I think I am just scratching the surface of this here and not in a particularly scientific way probably, but my conclusion so far is that consistent head size is far more significant than consistent weight.

My concern now is that I have no idea how to obtain pellets that are actually 5.52mm!! Anybody found a brand that is more consistent? 

Anybody want to buy 2,500 JSB Exact .22 5.52mm (NOT) pellets (-;

Asa
 
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