Q. Why do most people seem to shoot-five-shot groups? Surely the more shots you fire, the better the test of your gun’s accuracy?
A. In theory, you’re absolutely right. The point of shooting groups is to test consistency – and hence accuracy – especially if you are experimenting with variables such as a new pellet brand or head size. Any variation will become more apparent the more shots are fired, and similarly a superbly accurate rig will show its mettle the more shots are put into that group.
I once bought a particular rifle on the strength of somebody else’s accuracy test where they put 60 shots into one group. In that case, it was a PCP, and the rifle had been clamped. The accuracy displayed by that gun was staggering.
That is the crux of shooting a group. If you are shooting to test the accuracy of your kit, rather than your own shooting skills, then the gun should be kept as immobile as possible – and if it’s a PCP, that can certainly include clamping it. But for most of us that’s not practical, and we have to rely on ourselves to hold the gun steady, accompanied by aids such as bipods and shooting bags, where appropriate.
But despite all this extra help, two human factors come into play: muscle fatigue and mental fatigue. Even a well-supported gun will demand some physical input from the shooter, and every shot taken demands a mental effort too. Five shots is generally seen as a good compromise between testing the gun and testing your level of exhaustion. If you don’t think that’s enough, take a look a centrefire shooters, who will typically fire only three shots.
Two more factors come into play here that aren’t relevant to airguns: the fact that the barrel heats up and expands with each shot, plus the financial cost of the ammo, which can be around £1 a round. Suddenly a tin of pellets doesn’t seem quite so expensive…