Problem: Sudden pulses of gas, whether produced by internal combustion engines, pumps or guns cause even more noise. The traditional approach to suppressing noise pulses is to use expansion boxes containing sound deadening material and baffles. These, unfortunately, are both large, and significant cost items. While their use is accepted on cars and motorcycles, they are much to bulky to be fitted to the ends of air rifles.
Solution: Hugh Earl proprietor of Pax Guns and Prometheus, London based companies which make competition standard air rifles, and high performance lead-free pellets, has devised a most ingenious silencer.
Building on his previous career in noise and vibration suppression in the HVAC sector, he has taken advantage of the fact that the air emerging behind the pellet from a rifled barrel with a right hand twist tends to swirl clockwise. The plastic injection moulded internals of the "Phoenix Phantom sound moderator" therefore incorporate an anti-clockwise helix. The result is that noise from a pneumatic air rifle is reduced from 75 dBA to 42 dBA. The outer casing is made of carbon fibre reinforced composite for strength and light weight. The kit is supplied with a short length of lead wire, which is wound round the internals to reduce muzzle flip. The silencers are available for purchase from Parker-Hale in Petersfield.
Applications: It is fairly easy to use vanes to induce swirl in any exiting gas stream. Sending this through a helix rotated in the opposite sense provides a means of reducing noise in a smaller space and with less weight and cost than conventional mufflers and silencers. TS
Prometheus
Email to Parker-Hale
