The Importance Of Chronographs

PUBLISHED: 11:05 23 December 2020

The difference between batches of pellets can be enormous

The difference between batches of pellets can be enormous

Archant

Gary Chillingworth explains why every airgunner should own a chronograph to stay on the right side of the law!

The Combro just slips on the end of any rifleThe Combro just slips on the end of any rifle

Air rifles are amazing pieces of engineering, but like all mechanical objects, they need to be checked and looked after and one of the most important things that any shooter should own is a chronograph. We should never forget as responsible shooters, it is our duty to make sure that our rifles are always under the sub-12 ft.lbs. limit. A rifle shooting an 8.44grn pellet is limited to 800fps, and even though many UK guns are fitted with an anti-tamper device, designed to keep non-FAC rifles under 12 ft.lbs., it is still your responsibly to make sure that it’s legal.

There are many chronographs on the market today, from the Skan to the F1 and many in between, but these can cost many hundreds of pounds. There is a brilliant, cheap alternative, though. The Combro chronograph is a palm-sized chrono’ that fits on the end of a barrel; it costs about £50, and almost every top shooter I know owns one.

This chart shows two batches of identical pellets � you can see the difference in terminal speed downrange at 45 yardsThis chart shows two batches of identical pellets � you can see the difference in terminal speed downrange at 45 yards

CHEAP BUT ACCURATE

The Combro might be cheap, but it is exceptionally accurate and it’s probably better than my extremely expensive bench chronographs. The Combro also has a party piece that makes it stand head and shoulders above the competition, and this is its connectivity. You can purchase a cable that allows you to connect the Combro to a laptop; you can then start up the free software and spend the next 50 shots shooting at targets and having fun. The laptop tracks your shots and if you have a shot go low, look at the screen and it will tell you if that shot was under power, and vice versa if it goes high. After you have shot your string of pellets, you can look at the data and see if your rifle is as consistent as you would like.

A good PCP or springer should have the ability to fire 40 to 50 pellets all within about 20fps of its set power, on a single fill of the air cylinder. For example, my HFT500 is set at 775fps, and I would expect everything to be within 770-780fps, but this is a very top-end rifle. A cheaper rifle, in good order, should still be able to fire a pellet within say 765 and 785fps, and this 20fps spread will not massively affect the trajectory of the pellet. The problem is, when a rifle becomes old and might have a bit of rust on the hammer or springs that are losing their energy, then this spread of power can become erratic. I once had a rifle that would read anything from 720fps all the way up to 800fps, and that is on the verge of becoming an FAC rifle, illegal to own without a licence.

With this massive swing in power, the pellet at 40 yards can drop or rise an extra inch, and that is enough to make you miss a target, or even worse, injure an animal.

The R2a�s wide aperture is perfect for down range shootingThe R2a�s wide aperture is perfect for down range shooting

STAND-ALONE CHRONO’

If you want something that is bigger and that stands alone and is not fixed to the rifle, then I’d go for the R2A Ballistic Chronograph at £149. This chrono’ is different to many others because it has a 120mm gap between the sensors, and that makes it a very interesting prospect, for a number of reasons. The obvious one is that with such a large gap it’s harder to shoot it accidentally, and if you are using a chrono’ with a small aperture, this can be fine with a rifle, but lining up a pistol or a bow can be tricky. Also, the R2A is rated up to 6500fps and so is suitable for almost any form of firearm, and with a .308, you don’t want a metal chronograph directly in front of the barrel – shrapnel is not always your friend.

The other great thing about the R2a is, you can place it downrange and measure the ballistic coefficient of your pellets. To give you an example; with my HW100, if I use one brand of pellets they read 780fps at the muzzle, and 643fps at 45 yards. The next brand of pellets still read 780fps at the muzzle, but only read 600fps at 45 yards. This then tells me that brand A is a more efficient pellet for my rifle then brand B. There is no doubt that a faster pellet will take less wind and have a flatter trajectory, and there can also be a bigger difference between pellets with different head sizes.

You can set up the R2A so that it sits just in front of your muzzle, and depending on how high your scope is, you can shoot your targets and just look up at the display to see your velocity. This way, if you have a shot that hits high or low, you can see if there has been a power fluctuation at the muzzle.

The R2A will remember a 250 string of pellets and there is no doubt that this chronograph will help you to be more consistent and to choose the best pellet for your rifle. I like to have the Combro on my rifle and the R2A downrange so that I can then match the numbers up.

You can set the R2a in front of the peg and continue to shoot unimpededYou can set the R2a in front of the peg and continue to shoot unimpeded

BE WARNED

Then there are chronographs like the F1 and the Skan. The Skan is the ‘big daddy’ of the indoor chronographs, but it likes indoor lighting and sometimes in bright sunlight I have found that they can struggle – or at least mine does. Many shooters like the F1 and I have heard good things about them, but I have never used one on a regular basis, so I can’t really comment.

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This brings me to a very important piece of information. The person with the trophies in this article is Simon Vant. Simon is a good friend of mine and in 2018 he won the UKAHFT Nationals and the HFT World Championships, so he is one of the top shooters in the country. DO NOT LET HIM SHOOT YOUR CHRONOGRAPH! I love Simon, but he has shot my Skan, the UKAHFT’s chrono’ and my Combro – I have been told that he shot Richard Wood’s F1 chrono’ and I know that he has shot his own more than once. You have been warned!

Chronographs are an important tool and they will keep you on the correct side of the law, but they will also make sure that you keep your kit at peak performance. Having a chronograph like the R2A is an absolute must, for me. The ability to place it downrange and see how fast my pellets are hitting at 45 yards is a massive boon.

In the old days, using my Skan to do this was nerve-racking and I am amazed that I never killed the screen, but when you have the ability to pick a pellet that is 40fps faster at 45 yards, this is a huge advantage and it is this attention to detail that has certainly helped me over the years.

Testing is mandatory at all national eventsTesting is mandatory at all national events

I love my Combro. It lives in the boot of my car and has never let me down. My Skan is a great indoor piece of kit and is accurate and reliable. The R2A works in all lights and is the preferred chrono’ of the UKAHFT and HFT World Championships, so look at what you need and your budget and get yourself a chronograph.

The Skan is great, but shooting it at 45 yards is a bit scary and the dent top right, is courtesy of SimonThe Skan is great, but shooting it at 45 yards is a bit scary and the dent top right, is courtesy of Simon

This is Simon Vant, World Champion and Chrono KillerThis is Simon Vant, World Champion and Chrono Killer

If you have multiple Chrono�s, use them to make sure they all read the sameIf you have multiple Chrono�s, use them to make sure they all read the same

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