PUBLISHED: 09:31 31 October 2011 | UPDATED: 09:37 31 October 2011
To many airgun shooters, especially hunters, the third most vital part of their combo after the rifle and scope is a silencer...
To many airgun shooters, especially hunters, the third most vital part of their combo after the rifle and scope is a silencer. From simple tubes creating a very basic environment in which pressurised air can expand correctly called a plenum chamber to techno carbonfibre masterpieces full of springs and baffles, adding a silencer to an air rifle or pistol turns it from a twanging, thumping heavy metal group to a semisilent whisperer of slickly suppressed sound. Or can it?
Truth to tell, the more suitable name is actually moderator, because thats all the add-on is designed to do, moderate the sound, though some have rather more success than others.
For a start, pre-charged airguns can be more effectively moderated than springers because most of the sound generated by the action consists of the barely audible valve-springs high pitched ting. Much more noise is produced as the air leaves the barrel behind the pellet, but its relatively easy to mute this down. The simplest way is to allow it to expand into a larger diameter chamber before exiting the muzzle, but it can be even more effectively dampened by forcing the air to pass through a series of baffles, housed inside a similar large diameter tube. Each of these baffles, which can be purpose-shaped metal, plastic, felt or even in one renowned example, a hair curler, grabs a small quantity of the air as it rushes past until what finally emerges from the muzzle is, literally, a pale shadow of its former bold and thrusting self.
Pre-charged pneumatics, as weve said, are more easily moderated than springers because theres less going on inside to get the air on its way down the barrel. A spring-powered airgun, by comparison, is a bit of an animal with thumps, twangs, tinkles and thwacks all associated with the inevitable collision of the piston reaching the end wall of the compression chamber, creating a medley of sound and none of it capable of being muted or suppressed in any way by adding any extra to the barrel.
So theres not much point in adding a moderator to a springer, then? Well, yes there is, because while its undeniable that the springers action is noisier than a PCPs, the racket is going on just about as close as it can get to the shooters ear, so of course it can sound like a brass band tuning up. Downrange, where your target sits munching his breakfast the springers racket is no more intrusive than a high flying airliner or traffic on a distant A-road. The first he will know of it all will be when the air rifle pellet arrives and the sound behind that will have been muted by the moderator.
Theres another effect a moderator can have and thats to make the sound directional, which is why you can often swing on to another browsing bunny while your first, successfully culled, lies twitching on the ground. Aside from his late mates strange behaviour, rabbit number two is unaware of his danger because the sound of the shot was channeled so specifically to the target.
Incidentally, the springers sound level can be significantly reduced by expert tuning, where the stresses and strains of producing high-pressure air via the energy of a spring and piston are smoothed away with skilled polishing, balancing and tweaking.
For hunters, then, a silencer is a must-have but airgun shooters in general can benefit from muted sound levels. In competition, a noisy report can distract other shooters and cause a bit of friction as a result, while back garden plinkers will gain a definite benefit if the neighbours arent disturbed by all too obvious airgun reports.
Whatever the type and size of silencer you choose, its absolutely vital that it fits over the muzzle in perfect alignment with the bore of the barrel. If the muzzle of your airgun is not already threaded, a screw-on silencer is best fitted by a trained gunsmith but simpler sleeve-fit designs can just slide on to the barrel and fix in place by tightening a small grub-screw.
Once fitted, by the way, always check and be prepared to adjust your airguns zero because the silencer can have very slight effect on velocity and also, sometimes, trajectory too.