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Wisdom from the elders on pellet testing

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J

jpbrewer

Member
May 27, 2015
57
8
Georgia, United States
I did a search to see what I could find on pellet testing methodologies, and I could find none -- so I ask it here. Need some old hand expertise. 

I am target shooter and occasional hunter of squirrels and small vermin, and I wondered how all of you that are more experienced than me test your pellets. 

Yes, I know there are different head sizes and different pellet shapes - with domes generally being the most accurate. Yes, I know that JSBs, H&Ns and a few others are known for accuracy, what I am asking is how do you physically test. 

I have the luxury of testing at my close or far zero inside a large warehouse with no wind. 

I have a Wildcat, I have a vise rest. 

What distance should I shoot to compare?
How many shots to a group?
Should I use only a portion of the shot string?
What constitutes a material difference for a sub-MOA gun?

So basically, I am asking for a mid to expert level of testing knowledge. Hell, if you at going to do it, do it right. 

I am willing to by the samplers and try lots of pellets, just want to know the best way?
 
I shoot groups of ten unless the first few are just terrible. You want pellets that are accurate at the distance you need them to be used. PCP guns tend to like heaver pellets. You can start at 20-30 yards if they are grouping well move to 50 and see how they do. You can spend a lot of time and money trying every pellet out there. I find it saves time to start with the most commonly recommended ones first. JSB H&N etc.
 
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I read the air gun manufactures recommendation for pellets. Usually this will give me an idea of where to start. If there aren’t any recommendations, I’ll go to different web sites and read the pellet reviews. I look for the reviews of those people who are using the same make and model of air gun that I am. I will then purchase the highest rated pellet in several different head diameters. As an example, if the JSB domed, 14.3 grain pellets with a 5.52 head diameter were the highest rated, I would buy 1 tin of those and 1 tin of the H&N domed, 14.66 grain pellets with a 5.53 head diameter, 1 tin of the H&N domed, 14.66 grain pellets with a 5.54 head diameter, and so on. I then chronograph each of the pellets and keep detailed records of the tests results. The pellet with the Lowest Standard Deviation will be the most accurate. This first round of testing will tell you what head diameter your air gun shoots the best. You can then try pellets with that head diameter but with a different weight and from different manufactures. I have used this methodology with all of my air guns and it works. Keep in mind that heavy pellets with a slightly higher Standard Deviation should be more accurate at longer distances than light pellets with a slightly lower Standard Deviation. If you are using a high quality air gun the Standard Deviation should be in the single digits (1-9). If the Standard Deviation is not in the single digits, it’s not the best pellet for your air gun. Actual tests results: Air Arms TX200 with H&N Baracuda Green, Domed, 12.65 grains, Standard Deviation (1), Weihrauch HW90 with Air Arms Diabolo Field Heavy, 18 grains, Standard Deviation (3), Webley Alecto with H&N Baracuda Green, Domed, 12.50 grains, Standard Deviation (2). The highest Standard Deviation that I’ve ever had was (42). That was with the H&N Excite, 16.05 grains using the HW90 and they grouped like shot gun scatter. There is a formula for arriving at the statistically significant sample size when determining the Standard Deviation. However, I’m not going to discuss that here. Simply stated, the statistically significant sample size for determining Standard Deviation is the one in which the Standard Deviation can go no lower. If you shoot a 5 shot string and the Standard Deviation is 4 and then you shoot a 10 shot string with the same pellet and the Standard Deviation drops to 1 then the 10 shot string is statistically significant or the best sample size. I use a 14 shot string and drop the highest and lowest number. I do this because a slight change in angle across my chronograph will change the result and because I usually make at least one mistake. I used to plot the trajectory of the pellet with a calculator. Now there are free programs like “ChairGun” Pro available from Hawke Sporting Optics. I use this program for determining the optimal distance to sight-in my air guns. I set the “kill zone” at a (1/4) inch and then I plug-in different sight-in distances until I find the sight-in distance that allows my pellet to stay within the “kill zone” for the longest distance. As an example: My TX200 is sighted in at 21 yards. This sight-in distance allows my pellet to stay within the (1/4) “kill zone” from 16 yards though 42 yards. This covers the majority of my hunting shots with this air gun. Only if the quarry is less than 16 yards or more than 42 yards do I have to use holdover. Between these two points I just use the crosshairs and the pellet will hit within an (1/8) of an inch up or down. If you’re using a more powerful air gun (35-40fpe) you can extend the “kill zone”. As an example: with 38fpe and a 1/2 inch “kill zone” the pellet would remain within the “kill zone” from 17 yards through 53 yards. No thinking about holdover within that distance, just use the crosshairs and the pellet will hit within a 1/4 inch up or down. 
 
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