Air rifle pellet ballistics

Don Caswell

Air rifles are capable of excellent accuracy and small game hunting effectiveness. To realise this potential, the aspiring air-gunner needs to be aware of a range of issues. The two stand-out items in that list are choice of pellet and scope. The topic of air rifle scopes is too big to delve into here. This article focuses on the test results for a selection of .22 calibre pellets and how to choose what is the most appropriate pellet for your needs.

There are a broad range of pellets available for air rifles. I undertook an extensive program of shooting different .22 calibre pellets, measuring group size, muzzle velocity and terminal ballistic performance. I must thank the generous provision of pellets, and other assistance, from a number of Australian distributors, including Nioa, Alcock & Pierce, Tasco Sales Australia and Potter Firearms. This report would not have been possible without that willing support.

I used a Weihrauch HW100 PCP air rifle for the testing of the pellets. The rifle was shot off sandbags, and the crisp, light match trigger of the HW100 made for very precise shooting. Likewise, the Bushnell Engage 6-18×50 scope with side-focusing parallax adjustment down to 10m, and fine cross-hairs was a great assistance to accurate shooting. There was a good variety of poly and metal tip pellets provided along with the more conventional ones. Nearly all of those tipped pellets were all too long to fit in the magazine of the HW100, so, unfortunately, I could not test them. That was a shame, because some of these tipped pellets have shot well in my spring-powered air rifle.

Shooting was done at 25m. For each pellet type, multiple five-shot groups were taken. Velocities were measured with a Caldwell Ballistic Precision Premium chronograph. This device has light-emitting diode (LED) screens and makes the reliable measuring of air rifle pellet velocity possible. Ordinary chronographs often struggle to detect the small air rifle pellets passing over their sensors. That is doubly so if shooting under a roof, as I was. The Caldwell chronograph only missed a few measurements out of the many hundreds of shots fired over it, and those small number of shots were when I had inadvertently strayed well away from the centre measuring zone.

I used the phone app associated with the Caldwell for convenient data collection and statistics. This included the calculation of the true muzzle velocity using the measured distance of the chronograph from the muzzle. That only amounts to a few feet per second, but I thought it worthwhile for comparability, as over the many different days of shooting, the chronograph was not always in exactly the same location relative to the muzzle. I’ve included the standard deviation of the velocity measurements. It demonstrates, as I have noted before, that it has no discernible influence on accuracy.

The results of the testing of the pellets are shown in the table. The different pellets are listed in order of decreasing accuracy. While the results obtained are specific to the HW100, they are indicative of other makes and models. But, the fact that any particular pellet shoots well, or poorly, in the HW100 does not mean it will perform similarly in another type of air rifle.

The key takeaway here is that you need to test as wide a variety of pellets as you can lay your hands on. Alcock & Pierce sells a most useful sample pack which is ideal for trying half a dozen of the more popular H&N pellets. Most times you only need 20 pellets to determine if your rifle likes that brand or not. Ask around any of your buddies who shoot air rifles and see if you can’t garner some small samples of pellet types to try.

For target shooters, working off a solid bench rest, accuracy is the ultimate criteria for selecting any particular type of pellet. I am not a competitive shooter and my interest is in hunting small game for food and rural pest control. As with centrefire calibres, when hunting is the prime interest, the choice of ammunition is not simply based on accuracy. The main concern is terminal ballistic performance. It is vital that the projectile that hits your quarry possesses both shock and penetration. For a humane kill on any creature you set your sights on, you want the projectile to rapidly release its energy for maximum shock.

The other important point to remember is that the highest accuracy is not required for hunting. You cannot hope to duplicate in the field the accuracy you enjoy at the range. A good rifle and pellet combination that produces tiny, one-hole groups at the range cannot be expected to yield that in the field. The solid bench rest, precisely known level distance and maybe wind-sheltered situation, is not present in the field. The field shooter must often estimate the range, take a hasty and unsteady position and contend with wind and non-level shooting.

Given an accurate rifle, set on sandbag rests at the range, most shooters would produce similar group sizes to each other. Take that group of shooters into the field and give them the same rifle and ammo, and the results will vary greatly. Field accuracy is all about shooter technique and is specific to each individual. It is important to determine what your field accuracy is because that is the criteria for deciding whether you would use that pellet for hunting.

When you have found the most accurate pellet off the bench, you should use that pellet and shoot from a variety of field positions. In my case, the JSB Exact Jumbo Express produces consistent five-shot groups of about 6mm at 25m when shooting off the bench. When I tested myself, shooting groups at 25m from a variety of field positions, I found my group size was about 15mm. That means, for me, I am only interested in pellets that will group at 15mm or better off the bench. That is because, most times, I cannot shoot any better than that in the field.

Within the pellets that shoot at or better than 15mm at 25m from the bench, my interest is then on the terminal ballistic performance. I determine that by shooting at ballistic media and examining the exit hole. I have tried a variety of ballistic media over the years, and these days, for air rifles, I rely on bars of cheap laundry soap. The soap is very consistent in size and density and is inexpensive and convenient to use. I do the soap test at typical and maximum field ranges. That is 25m and 50m. The pellet that leaves the biggest hole is the pellet that delivers the greatest shock to the target.

When I tested the 18.2-grain H&N Baracuda Hunter, I found it shot better than my 15mm criteria and left a generous exit hole in the soap. That prompted a break in the range sessions and a quick bunny-hunting foray. The 18.2-grain, hollow-point H&N Baracuda Hunter, at a muzzle velocity of about 865fps, proved to be highly effective on the local bunnies. I enjoyed emphatic one-shot kills at ranges from 10m to 50m. On the basis of achievable accuracy and retained energy, I draw the line at 50m when hunting small game with the HW100.

My testing of a great range of pellets has allowed me to chose, with confidence, the best hunting pellet for the rifle. That knowledge and the practising of good field shooting technique means I can confidently target small game and pests, for emphatic humane kills, out to 50m.

 

Pellet test results

 

Pellet Weight grains 25m group mm Energy ft-lb MV fps Std dev
JSB Exact Jumbo Express 14.4 6 29.7 963 2
H&N Baracuda Accurate Heavy 21.1 7 31.8 824 1
Diana Exact Jumbo Diablo 15.9 9 30.1 923 2
H&N Baracuda Green 12.4 10 28.4 1018 2
H&N Sniper Light 14 10 28.5 957 14
JSB Exact Jumbo 15.9 10 30.2 925 5
H&N Sniper Magnum 18 10 30.8 878 6
H&N Piledriver 30 11 31.7 690 4
H&N Sport Field Target Trophy 14.7 11 29.6 953 3
H&N Baracuda Hunter 18.2 13 30.5 868 6
H&N Baracuda Power 21.1 13 29.2 789 4
BSA Target 18.5 13 31 868 8
BSA Blue Star 18.2 13 30.4 867 10
Skenco UltraShock HP 16.7 16 30.3 904 1
Gamo TS-18 18 18 31.5 887 9
BSA Red Star 18.2 18 30.1 863 6
H&N Crow Magnum 18.2 20 31.1 877 4
RWS Super Field 15.9 20 30.1 923 2
BSA Elite 15.4 21 30.5 944 8
BSA Fury 18.5 33 37 949 5
Coal Field Target 250WP 15.4 34 30.3 941 2
Napier Power Hunter (lubed) 15.4 40 31 951 6
Coal Fenix FX550 17 42 30.5 899 5
Milbro TR22 14.2 49 29.2 963 5
H&N Hornet (metal tip) 16 54 30.3 923 2
Napier Power UPH (lubed) 14.5 60 29.7 960 2
H&N Silver Point 17.1 64 30.9 901 2
Milbro Jet 13.4 75 29.8 1002 7
Milbro Caledonian 13.3 78 28.9 990 2
Diana Sport Diablo 13.7 80 30.4 1000 6
Pro-Pell 13.3 82 29.5 1000 11
EXP ‑ Extra Power Hunting Pellets 13.3 86 27.3 962 7
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