Is there a difference in accuracy between an air rifle with a 9+" barrel and one with a 15+" barrel?
PUBLISHED: 13:35 04 April 2017 | UPDATED: 13:35 04 April 2017
Differing revolver barrel lengths make the world of difference to performance but does the same apply to air rifles?
Q: I am a relative newcomer to the air rifle world, and I’m finding that there are many things which puzzle me. For instance, I have been told that there is no difference in accuracy between a rifle with a 9+” barrel and one with a 15+” barrel, assuming that the internal works are the same in each instance. (Prosport & TX200). How can this be? I know that there is a world of difference in performance between a .357 revolver with a 2” barrel and the same thing with a 6” barrel. Does not this argument apply to air rifle barrel lengths?
A: If we consider the two spring airguns, recoil comes into the equation, and the shorter barrelled one that gets the pellet out of the muzzle sooner is potentially more accurate on that score, although there will be slightly more muzzle rise during recoil due to there being less weight at the muzzle, which favours the longer barrel. Second, and contrary to popular belief, the pellet does not stop accelerating after 8” of travel up the barrel, so the 15” barrel will produce slightly higher muzzle velocity and have a slightly flatter trajectory, unless the rifle with the shorter barrel uses more spring energy to achieve the same muzzle velocity, which means slightly more recoil, so in that respect, the more energy efficient, longer barrel seems to have the advantage.
Recoil aside, let’s look at the PCP, which is effectively recoilless. PCP rifles are far more dependent on barrel length than spring airguns, and one with a short barrel would be hopelessly inefficient, which is why they all have fairly long barrels, although PCP pistols are another matter, and if you need proof that a long barrel is not essential for accuracy then look no further than the stunning accuracy of a match air pistol with a barrel of 9.5” or less.
When two airguns are fitted with the same barrel, but in different lengths, the important point is that the barrels are long enough to get the pellet spinning, and that the pellet is correctly lined up as it reaches the muzzle, so that pellets all exit the muzzle with enough spin to keep them stable in flight, and all pointing in the same direction. Given the accuracy potential of the Pro Sport with its 9.5” barrel, it clearly meets both criteria.