Getting into Field Target Shooting Part 2

In 25 years of competing at regional, national and international level, I never encountered anyone using anything else but .177” calibre rifles. Let me say now, this has nothing to do with which is the most accurate calibre. It does however, have a lot to do with two other reasons. Speed and trajectory, both of which are interconnected, this is why in this instance, smallest is best!

Fighting the curve

The .22 and .25 must send their pellets out of the muzzle slower than the .177 in order to comply with the 12 ft/lb law. As legally no unlicensed air rifle can produce over this energy figure, otherwise it becomes a Section 1 Firearm! Slower means a more pronounced trajectory. This is due to the fact that the .22 and .25 pellets weigh more than their smaller brother and this is where `kinetic energy` works against us, as legal air rifle owners. If we could fire the larger calibre pellets at the same speed, there would not be a trajectory problem. In fact, they would outperform the tiny .177 at extreme ranges. There is no real difference in accuracy between the three, as the grouping picture shows.

Imagine throwing a small pebble at the base of a tree some 20 yards away. Now imagine throwing a house brick at the same tree base. Your house brick needs to be thrown a lot higher initially to land in the same spot. But OUCH! I know which one I would rather be hit by. This is an example of trajectory and kinetic energy at work.

In the world of licensed Section 1 Firearms, the powder charge can be increased to propel bullets at higher velocities in relation to their weight, and therefore compensate for trajectory with little or no restriction by law. If we start doing this with the air rifle pellet, we will exceed the legal 12 ft/lb limit for muzzle energy.

Therefore, it makes sense to use the flattest shooting combination available when aiming at targets of varying distances!

We can delve lightly into the world of external ballistics to get a better understanding of the differences. I say yards, giving an effective range of 35, possibly 40 in the right hands. The .177 can be zeroed out to 35 or even 40 yards for an effective range of 55 yards, up to 60. Not on live quarry I hasten to add, and only because pellet placement becomes an issue at these extreme ranges. There is plenty of energy left in a .177 out to 65 yards plus to despatch small game, given the caveat that placement is the key to a clean kill.

 

The butter test

Take a look at the `butter` test, or in this case, margarine `cause you can’t tell the difference; no expense spared for Shooting Sports! Three packs stood out at 30 yards and three 12ft/lb rifles each fired into them with domed pellets of .177, 22 and .25 calibres weighing 8.4, 15.9, and 24.38-grains.

In pic 2, it can be seen that the entry hole of each pellet has an increasing effect as the calibre increases. In Pic 3, the exit holes show how the kinetic energy of each pellet has had a different effect on the margarine.

The .177 has released some of its energy, causing a small expansion and leaving a funnel on the exit. The .22 has had a bigger effect inside the pack and hardly left any funnel at all as it released more energy inside before exiting. The .25 exit hole is dramatically larger with no funnel at all, but also notice how large the cavity is through the pack, causing it to bulge on the outside.

This is an example of the kinetic energy being transferred to the target, despite all three having the same initial muzzle energy of just under 12 ft/lb. What this tells us is that its horses for courses. For close work, up to 30 yards maximum, the .25 is a formidable calibre; good in barns for vermin like rats or pigeons.

Everybody’s favourite, the .22, can step out a bit further for the same quarry or rabbits up to 40 yards depending on initial zero point.

 

Fast ‘n’ flat

But for target, the tiny .177 has the highest speed and therefore the flattest trajectory. This equates to less time in the air and therefore less effect from the elements at a given velocity. The fact that its kinetic energy is of no consequence, as it still retains plenty of steam to knock a steel target down at 55 yards and beyond.

So, to all you budding FT shooters out there, I just hope you get advice or read this before doing what most first time air rifle buyers do, and choose your calibre wisely to suit your needs. I like them all and always try to choose the right one for the job. But the right one for Target, without question, is .177! Next month we will look at choosing the right scope/mounts combination for wither FT or HFT and fitting them correctly.