Pellet Tolerance

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Apply a slight amount of silicone lubricant inside the barrel and use a wooden dowel or some other softer than the bore material to push a soft lead pellet through the bore and measure it with a caliper guage to know the smallest portion of the barrel. Many airgun barrels are choked near the muzzle but not all are. You can research to find out if your barrel is choked or not. You can also go into the breech end a bit then reverse back out to check that portion. 
 
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At the end of the day the best way to get the most out of your airguns is to try some friends pellets and or sample packs because every gun will have it's favorite pellet or pellets depending on your wants and needs. No two guns are exactly the same. Hopefully you'll nail it down quickly but not always. That's part of the fun of it when you get the best pellet! : )
 
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Jon,

Based on what I have measured personally, and the reports of my customers, I propose that when purchasing a high quality pellet, pellets should have 95% of the normal tin quantity with +/- 0.01 mm of the nominal size, i.e. if you are purchasing 4.52 mm pellets, 4.51/4.53 is the acceptable distribution with a limit of 5% being outside those limits. 

Now, I contend that many tins will not meet those criteria, and that some tins will have a shift of up to 0.02 mm in their mean size. In such cases, you would find few pellets that are actually the desired 4.52 mm, for example.

I have never seen any manufacturer make such a claim, and it is a shame that they don't!
 
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After washing 500 JSB 18.13 in a combination of Hornady Sonic Clean, Dawn and water in a heated sonic mini washer I began sorting them by weight. I was totally surprised after a short time sorting (photo) as the weights were all over the place. While doing this I was checking the skirts and found about 5% bent/deformed. They've been treated with Napier Power Pellet Lubricant and are in separate 2 inch screw top tins. So far my Wildcat .22 likes the 18.13, and I have no plans to check individual head diameters. The whole process is to pass the time on non-shooting days and to see if accuracy can be even better. Scale is a Sharpshooter.

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Quoddy, Great work on the washing weighing and lubing but do your self a favor and get a "pelletgage" and check the head sizes! Unless you are shooting distances longer than 55 yards the weight will mean a whole lot less than the head size will. I have found with JSB pellets what is marked on the can (head size) means nothing as to what is in the tin!! they vary a great deal and that will effect you POI more than weight will at the distances we normally shoot at.
Now if you are going for longer range accuracy it all comes into play! I'm glad to see us .177 cal. shooters are not the only ones that are disgusted with JSB's quality control ! They might get a hint!!
Welcome to the extremely boring pastime of pellet sorting!! J.L.
 
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I have a good friend in Texas who shoots field target with his Air Arms springer. His skill has improved to placing at AFTA nationals. He has found Air Arms pellets to be best, but began sorting pellets for matches a couple of years ago. He sent this image last week, showing results of about 300 he sorted from a new tin of AA 8.4 grain, "4.51 mm" pellets. He does this while watching TV and the photo shows the results of more than one session, as he sorts into tins marked by gaged head size. He said that these last 300 he sorted : "10% were 4.48 mm, 65% were 4.49, and 25% were 4.50". You can see that very few are actually 4.51. Consider that the pellet is called 4.51 if it clears the 4.51 aperture, so they would be a bit smaller than that diameter. He did not find a single pellet that did not clear 4.50 mm aperture. My friend says that he can use 4.48 to 4.52 in his rifle, but that matching the size and shooting only one size at a given zero point will give him better patterns. My friend is an experience engineer who works in a field requiring mechanical precision, and he did not readily accept the premise that a Pelletgage was really needed. His controlled practice sessions convinced him.

That's my take, too. You may very well think that head size is not critical for your gun, but you would see much bigger patterns if you were shooting pellets with the range of 4.48-4.50 all mixed, for instance.

Air Arms sells their Diabolo Field pellets, 8.4 grain, in 4.50, 4.51, and 4.52 mm sizes. The two issues you MAY find is that a new tin is, say. 0.03 mm smaller than the last in. Or worse, you have a mixture of 4.48-4.51 mm in your tin. And a third issue is when you shoot that 4.46 mm pellet in a match and see the notorious "flyer" about an inch and a half off the aimpoint at 30 yards.

Now, you need to know FIRST if your gun is "pellet sensitive" and what size works best. Then you are left with the concern of being able to get that size, regardless of what you buy. And I have seen many reports like this one. Although I'm still a dedicated JSB shooter myself, I sort for 4.51 or 4.52 for my Marauder (with Lothar Walther barrel). I have found that the 10.3 grain JSB Exact are pretty good, but I check every tin, and for most matches, I sort for one size and zero my rifle on the range with that size. I DO see the occasional pellet that will be +/- 0.04 and am convinced accuracy is affected for my rifle.

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Pellet manufacturers have lapses in their process controls, and this lack of control isn't predictable. Those who have gotten six good tins ahd have been shooting them for a whole season may think it is all silliness.

Good luck shooting!

 
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There is one well known dealer who evaluated the Pelletgage early on. I was told that while they agreed it was a good product, they preferred not to put a tool in "picky" buyers hands that might result in the return of pellets being sold. ;-)

My own career was in the fabrication and assembly of electronic assemblies, and the precision needed to do this work on ever shrinking tolerance was the background for developing Pelletgage. I have taken a serious look at the inspection and sorting mechanisms needed to select/reject and "bin out" pellets. I was also told that it had been done by one of the major manufacturers. Suffice to say, it should be possible to hold +/= 0.01 mm diameter, but I think the process yield for swaging is not going to be consistently good. This means that there would need to be continuous measurement and selection for this tolerance.

I've seen pellet tins with nearly ever one of five hundred that fit one aperture of a Pelletgage, putting the tolerance at about +/- 0.005 mm or better. So it is possible, but reports I see lately indicate that it is NOT consistent, and the trend seems adverse.

Take a look at what Hard Air Magazine is reporting with their excellent pellet reviews.
https://hardairmagazine.com/category/reviews/airgun-pellet-test-reviews/
 
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As I said before I don't know why they bother putting the sticker on the bottom of the tin as it fraudulent! At least the ones you get from Pyramyd with the large white bar-code sticker on the bottom don't claim to be any head size so you can't really complain!! I have tried to find 10.34's that were 4.51 or 4.52 but out of 20 or so tins from many different vendors I may have found 100 or so pellets and they varied greatly in weight! SO!! I have given up trying as I am tired of wasting untold hours sorting only to find very little that my rifles will shoot well. I probably would not gripe about it so much if they didn't false advertise the contents!!!!! Oh well! Rant over once again!! J.L.
 
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