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Pellet Velocity & Improving Accuracy Guide

Pellet Velocity & Improving Accuracy Guide

For quite some time I have had a theory which considers that pellets react differently at varying speeds in feet per second. (fps). The aerodynamics of a pellet are not that brilliant, so the effect of air pressure and turbulence when travelling at speed through the air must have a detrimental impact on the pellets trajectory and consistency.


We have often heard it said, "this pellet doesn't suit my gun", or, "that pellet is not compatible with my barrel". Is it non compatibility or non suitability between pellet and gun? or is it the power of the air rifle, and more importantly, the critical speed at which the pellet leaves the gun which controls the pellets accuracy?.

With the emergence of the PCP, and in some cases, the ability to easily adjust the guns output pressure (lb/sq"), it is now possible to test this theory, and by increasing the pellets performance, we should improve the grouping. It is anticipated that in some cases the guns output pressure will be reduced, and in other instances the guns output pressure will be increased, depending on the particular pellet selected and its characteristics.

Due to the stringent air rifle laws in the UK, this test should not be carried out by inexperienced air gun users, and should not be attempted if the correct equipment is not available. The maximum output pressure most always remain below 12ft/lbs.

The equipment required to conduct this test would include a PCP air rifle with an adjustable pressure valve and preferably a regulator, cleaned sized lubricated and weighed pellets which are already known to be reasonably compatible with you gun, a set of targets positioned at 60 yards (one target for each test), a good quality scope, a full divers bottle, chronograph, a steady pair of hands, and a rifle rest.. The distance you set your target is totally down to your preferred range, but not too close.

Fire a group of pellets (say 10) at the first target noting the grouping, and ensuring your guns charge pressure is between 160 bar and 135 bar, or your preferred "sweet spot", if using a regulator. Keep checking this pressure, and top up accordingly.

With the benefit of your chronograph and some pellets, reduce the output pressure of your rifle say by 1/2ft/lbs and repeat the above by firing another 10 pellets at a new target. Then reduce a further 1/2ft/lbs and repeat above, and continue this exercise down to as low as 9.5ft/lbs Then gradually increase the pressure in your gun by 1/2ft/lbs stages, and repeat the above firing of 10 pellets at each new target until you have reached the maximum safe working pressure output of the gun. Then inspect all the targets and find the tightest grouping of pellets. Do not be surprised if it's not the highest ft/lbs setting that produces the tightest grouping. The target that does show the tightest grouping is probably the most efficient combination of your gun and the selected pellet at the most effective speed and ft/lbs pressure.

This exercise can then be carried out for other pellets for use in both targeting and hunting, making sure you record the rifles output pressure which produced the best result.

This exercise is at best, a way to improve your guns performance, and at worst, a great way to spend some time improving your shooting skills.
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