71 Gary Chillingworth answers a reader’s letter about modern airguns
Gary Chillingworth discusses the what and why of our airguns
“you have to research what sort of style of shooting you want to do, before you spend your hard-earned money”
Afew weeks ago, I received an email from reader, Tony Woodward. Now, this email was different from the vast majority of emails I get because it wasn’t threating my life and it didn’t finish with the line, ‘ I know where you live’, but to be honest, most of those emails come from Phill, the editor, and not you fine readers of Air Gunner.
Tony asked if I could provide a brief outline of a modern air rifle, something that could explain all the parts of a modern airgun, and also what they do and why we use them. He went on to say that there are a lot of people coming into the sport, and even though words like ‘ hamster’ and ‘comb’ are the norm to hacks like me, not everyone knows what I’m on about, so here is my attempt at airguns 101.
To start, let’s have a look at the woodwork. A modern air rifle’s stock is as complex as it is simple and you have to research what sort of style of shooting you want to do, before you spend your hard- earned money.
When we look at a rifle like the HW100, you can see that the cheek piece – the area where you rest your cheekbone – is at almost the same level as the scope’s dovetail. This is the area on top of the main body of the gun, where the scope attaches. So, when you attach a scope to the rail, the centre of the scopes rear lens will be a good two to three inches above the top of the cheek piece; the cheek piece is also called ‘ the comb’. Rifles like this are designed to be shot with the rifle in the shoulder and the shooter’s neck in a vertical position. So, if your shooting will be from a bipod – kneeling, sitting or standing – or if you are an HFT shooter who will be shooting high up the peg, then this sort of stock is perfect for you. These types of stock are often referred to as hunter-style stocks.
The next style of stock is where all the bells and whistles start getting added and these are target stocks. Now, for Hunter Field Target (HFT) the vast majority of shooters choose to rest the toe of the butt of the rifle on the ground because this gives the rifle a huge amount of stability. HFT is predominantly shot from the prone ( lying down) position and when you lie down, it is hard, nigh- on impossible, to have your neck in the vertical position. Your head will need to be tipped back and if you have a hunter-style stock with the butt on the floor – the
butt is the rubber butt pad that goes into the shoulder, your eye will be located about two to three inches above the scope, unless you are a supermodel and are only 8” thick. So, to combat this, you need to lift up the rear of the rifle and to do this, we use an adjustable butt pad.
These pads come in many different guises, from the standard adjustable, which just goes up and down, to a butt hook that has paddles, which for HFT can’t be more then 2¼” long. An adjustable pad will enable you to lift the back end of the rifle by a few inches and this makes the rifle much easier to shoot. There is also a good chance that even with an adjustable pad, you will struggle to place your cheekbone on the rifle’s comb (cheekpiece) because it might still be too low. This is where the next piece of kit comes in.
ADJUSTABLE CHEEK PIECE
In my opinion, the adjustable cheek piece is the most important part on a modern air rifle and should come as standard with all high performance rifles. When you are lying down with the butt on the deck, you can raise the cheek piece to just below the level of the scope. This way you can rest your cheekbone on the rifle’s comb, and with some minute adjustments, you can ensure that your eye will always be in the centre of the scope. This repeatability is the key to accurate and consistent shooting. However, if you have purchased a rifle without an adjustable cheek piece, then you can make one from pipe lagging or Kydex. Check out how to do this in back issues of Air Gunner.
Now that the back end of the rifle has been lifted and the cheek piece has been adjusted, you might find that the fore end is too shallow and that you either have to grip high up a peg or branch, instead of resting your leading hand on the ground and placing the rifle on top. To give yourself extra depth at the front of the gun, you can fit a palm shelf, also referred to a as a hamster. If you have a rifle like an HFT 500 then this is simple; you can buy a stock palm shelf and attach it to the rifle rail. Some rifles have a metal channel located under the stock. This is known as ‘an accessory rail’ and can be used to fit hamsters, bipods and even torches, but if you have a gun without a rail, you will need to attach the hamster by drilling the stock and installing some insert nuts. This will give you something into which to screw a hamster. Essentially, all a hamster does is help the shooter adjust the depth of the rifle by varying the length of the bolts you use to attach it to the stock.
The next item that causes some confusion is the difference between a regulated and unregulated rifle.
Rifles like the stunning Air Arms S400 are the ultimate unregulated rifle. It has
“shooters choose to rest the toe of the butt of the rifle on the ground because this gives the rifle a huge amount of stability”
a cylinder of air and a valve. When you pull the trigger, the valve opens and a chunk of air is released – ‘chunck’ is the technical term – and this forces the pellet down the barrel. The only real problem with a standard valve, or ‘ knock open’ valve, as it is better known, is that in the past, when you filled the rifle before a shoot there could be a difference in velocity of the pellet depending on how much air you had in the rifle. For example, let’s say we fill the gun to 190bar and after 60 shots it had 110bar at the end of the shoot. If you shot past that 110bar, then the pellet speed could drop and change your point of impact.
Shooters would take a rifle and learn where the sweet spot was and you would often find that a rifle would give a consistent speed between say 175bar and 120bar, so you would fill to 180bar, then fire three or four shots off, then you would have 40 shots within the rifles sweet spot. So, as long as you knew your gun, having an unregulated rifle was never an issue.
A regulator, however, in its most basic sense, is a second air cylinder called ‘a firing chamber’. It is placed between the main cylinder and the barrel. Using a system of springs and valves, this second cylinder is filled from the primary cylinder and after a pellet is fired. As the air to fire the pellet only ever comes from the firing chamber, you have a much more consistent source, and by adjusting the tension of the adjuster spring, you can adjust the power of your rifle up to 12 ft.lbs. This is the basics of a mechanical regulator, but Daystate have an electronic regulator system that they refer to as ‘ MCT technology’, and Weihrauch have an air metering system, but they are all essentially the same thing.
SILENCERS AND STRIPPERS
Silencers are a great thing. They enable us to shoot quietly, and if you are shooting at home or you want to bag a few bunnies, then buying a rifle with a silencer can be a real boon. If you think you might want a quiet rifle then purchase a carbine. This is a rifle with a shorter barrel and then when you attach the silencer, you will have a gun that is quiet and still as accurate as a full-length rifle. The only downside is that a carbine sometimes uses slightly more air.
Strippers are a different beast; they are loud and are all about performance. When you fire an air rifle, the pellets leave the barrel and supersonic air overtakes the pellet almost immediately, causing it to wobble in flight. This will slow the pellet down and a slower pellet will be more affected by the wind. An air stripper has a set of vents that forces the supersonic air away and thus enables the pellet to fly flatter and truer.
A silencer actually does a very similar job, it just uses baffles instead of vents, but there is no doubt that on a rifle that has a slightly less than perfect barrel, a wellfitted stripper or silencer can certainly help accuracy.
We will cover scopes in the next issue and let me know if there is anything else you want me to look at.
This HW100 is being shot from the shoulder and this is the perfect way to use a hunter stock
This is my spare spring rifle with all my homemade mods
Here you see Paul’s face on the adjustable cheekpiece and it is perfectly centred on the scope
A bespoke stock enables the shooter to rest his cheek on the comb and the rifle on his planted hand
The science of the airstripper is confusing, but they do work
The blue line indicates pellet flight. The red line indicates air blast