One of the things that has always bothered me about shooting air guns, is the lack of control we have over the ammunition we shoot. In the powder burner world, I loaded all of my centerfire ammo. I had varmint rifles built to bench rest specifications, and used bench rest loading methods to handload ammunition for them. I had a lot of control over the processes used to load precision ammo, and the on target, long range results were well worth the efforts.
I could turn case necks, weigh powder charges to within a tenth of a grain, uniform flash holes and primer pockets, experiment with different powders, bullets and primers, try different bullet seating depths, and check my loaded rounds for near perfect concentricity. I did all of these things to eliminate as many variables from the ammunition as possible.
In the air gun world, none of that holds true. About all we can do, is to buy different pellets, from different manufacturers and shoot them. If you find one or two that shoot well, great. The problem is, the next time you buy the same brand and type of pellet, they may or may not shoot as well as the last ones did. Pellets from one manufacturing lot to another can vary a lot, in the accuracy department, in a given gun.
I have taken to weight sorting my hunting pellets, and that has helped to catch the serious outliers, whether heavy or light. However, I haven't found a repeatable, quick, and accurate way to get the one critical piece of data that I really want to know, and that is the head diameters of the pellets that I shoot.
I gave up a long time ago trying to measure the head diameters of lead pellets using a micrometer or digital caliper. I just could not get accurate and repeatable numbers. I have found pellet head diameter to be a very critical part of getting a high degree of accuracy from my guns, but until now, I didn't have an accurate way to measure the heads of the pellets that they were shooting the best. It was pretty much the SWAG system.
As with my powder burner ammo, I want to be able to eliminate as many variables from my air gun ammunition as possible. I know that the weight variation in a tin of pellets can sometimes be substantial. For example, below is a picture of the results of weight sorting .25 caliber Beeman Kodiak Match pellets. The advertised weight is 31.02 grains. I was surprised to see a full one grain weight spread across the tin, and they didn't shoot any better than the non match version of the same pellet.
I know from experience, that the head diameters of pellets from the same tin can also vary substantially. Not by measuring them, but by how they feel while being inserted into the breech of my FWB 300S. Some are a snug fit, and shoot great. Others are loose, to very loose, and don't shoot well at all. The actual head size may not be close to what is printed on the tin by the manufacturer. Another problem, is when you buy a few more tins of the same pellet, six months later, and the head diameters turn out to be different from the ones that were shooting so well. This can cause the new pellets to have a negative impact on accuracy. Very frustrating when you are trying to extract top accuracy from a given gun.
However, an exciting new product from PelletGage.com will change all of that. The brains behind the tool, is a gentleman by the name of Jerry Cupples. Using state of the art laser equipment, Jerry has developed a go-nogo gage, for finding pellet head diameters. It is very accurate, easy to use, and repeatable. I purchased one in .22, and wow, what an eye opener it has been. Very interesting to see what we are actually getting, versus what we think we are getting when we buy pellets.
Rather than try to tell the story of how this tool came about, I'll just include a link here, (How PelletGage came to be) to Jerry's site and let him tell it in his own words.
Now that I have a precision tool that I can easily use to check pellet head diameters, there are a bunch of different projects that I will be working on. The first one, is to see how close to the manufacturers labeled head size, the pellets in a given tin actually are.
I went through my pellet stash and pulled out four different pellets, by three different manufacturers, that have the head size printed on the tin. The first pellet up will be the JSB Straton Jumbo, .22 caliber pellet. The head size is specified to be 5.50mm.
To help keep things organized, I'm using another new product called the, Speedy Pellet Inspector by (airgunproducts.com). I'll have more to say about this product in a future blog story. I selected 50 pellets, at random from the tin, and using the PelletGage, measured each pellet head. The picture below shows how the heads actually measured compared to the head size specified on the tin.
The PelletGage with JSB Straton's resting on the 5.50, and 5.51mm size apertures, and another one that has dropped through the 5.52mm aperture. This shows how the "go no-go" design of the gage works.
Next up, we'll take a look at the DYNAMIC PCP-2, tin alloy pellet. I've been shooting these now for the better part of eight years, and have had a lot of success with them in most of my PCP's. They have been one of the most consistent pellets, weight wise, of any pellet I have tested. Using the PelletGage, I now know that they are also very, very consistent, relative to the manufacturers specified head size of 5.54mm.
Again, selecting 50 pellets at random from the container, and using the PelletGage, I measured each pellet head diameter. The picture below shows the result of that test.
This time, just to be different, I selected sixty pellets at random, and put them through the PelletGage to determine their actual head diameters. Below, are the results of that effort.
Since this story is already longer than I intended, I'll pick up the fourth pellet, along with a few others, at another time. I think this gives a pretty good idea though, of what the PelletGage brings to the party, when trying to eliminate ammunition variables, while pursuing accuracy with our air guns.
This has been a very interesting, and enlightening project. It confirms what I have suspected for a long time, and that is, for the most part, the head diameters of various pellets are what they are, not what the manufacturers put on the tins. The reality is, I've had no clue as to what the actual head sizes are of most of the lead pellets that my PCP's shoot well.
The good news though is, with the introduction of the PelletGage, those of us that care about such things, as pellet head diameters, now have an accurate way to eliminate one of the variables, introduced into air gun ammunition at the factories. We can now hand select the head sizes that we want from the tins that we buy. I for one, will from now on, be taking any published head size information, from most manufacturers, with a huge grain of salt.
I'm not in any way associated with the PelletGage Company. I just want to help spread the word on a very innovative, and worthwhile tool for accuracy minded air gunners.
You can check it out for yourself at, (PelletGage.com). They are now available in .177, .20, .22, .25, and .30 calibers.
This tool opens the door to all kinds of experimenting, and my brain is going into sensory overload thinking of the possibilities. I have a .25 caliber PelletGage on the road to me, and I'm looking forward to being able to check the head sizes on my .25 cal ammunition also.
Like with a lot of things in life, size matters, and this tool will help you select the pellet head diameters that are the most accurate in your guns.
Stay tuned, more to follow.
Until next time, thanks for reading.
Addendum: I want to add this information, and my experience, as it relates to the DYNAMIC PCP-2, and the two available head sizes. Those sizes are, 5.54mm and 5.56mm.
Back in 2007 I had a situation arise on a ranch that I hunted ground squirrels on. The owners suddenly decided that the use of lead ammunition, of all types, was banned on their property. That meant that I had to come up with a non-lead pellet for my airguns, or stop hunting on that ranch.
My search for a non-lead pellet ultimately took me to England, and the DYNAMIC BRAND tin alloy pellets. I explained to the factory rep, that I would be shooting them out of an FX 2000 .22. He then suggested the PCP-2, for use in that rifle, and was kind enough to send me a box of both the 5.54mm and 5.56mm head sizes to try.
I remember being elated, when the first five tin pellets I fired at paper, at 55 yards, went into a half inch group. They were the 5.54mm head size. I then tried the same thing with the 5.56mm version, and they went into an inch and a half group. I switched back to the 5.54mm version, and shot another half inch five shot group. I went back to the 5.56mm version, and shot another large group. I bought twenty boxes of the 5.54mm version shipped directly from England.
The difference in head size, between the two pellets, is only .02mm, (.0008) but when shot from my FX 2000, that little difference in head size made a huge difference in group size.
It's nice to finally have a tool where I'll be able to accurately sort pellets by head diameter, and to also take a pellet that a particular gun is shooting well, measure the head size, and sort pellets for that rifle by that specific number.