Air
Shroud Damper
Shroud Damper
This is one of those undervalued little accessories that sometimes makes a small difference, but sometimes makes a big one. It is a sound damping system designed to fit inside the reflex volume (shroud) of a rifle, which improves the overall sound attenuation with or without a moderator.
The most obvious necessity for a shroud damper is on rifles where the shroud pings with every shot, a phenomenon sometimes mistaken for air-tube ping. That is far from its only application however, as almost any shrouded air rifle will benefit. There is a great deal of undesirable sound which continues to exit the shroud long after the uncorking peak of the pellet leaving. This caused by pressure waves running up and down the inside of the shroud. The shroud damper reduces that sound by disrupting and attenuating those pressure waves. More information can be found here.
Installation is easy. Rings can either be slipped over the end of the barrel or applied around the barrel via a slit. The rubber disc goes at the rearmost point in the shroud, skin side facing the action, followed by the three foam donuts. Be sure to occlude any shroud vents or ports, not only because they make your rifle louder, but also rifles of sufficient power can cause the damper to be extruded through them. Your shroud can then be reinstalled over-top.
No Damper
Damper
At left are two traces showing an otherwise factory-stock FX Crown .30 caliber with its shroud extended both before and after the addition of a shroud damper. Clearly, the damper is reducing the post-peak sound signature. The difference between the two tests was clearly audible.
Installation Notes:
FX Crown - model listed is for the original (non-superlite) barrel type. Improved performance is achieved by moving the shroud stop all the way to the rear, thereby increasing effective shroud volume with no increase in overall rifle length.
American Air Arms - shroud retainer is threaded to the barrel end. Remove the moderator, and use a pin-tool, round nose pliers, or strap wrench to remove the shroud retainer. If the action nut is vented, insert a small plastic ring or equivalent between the barrel and action nut to block off said vents (they increase the rifle’s sound signature) and give the shroud damper a flat broad surface on which to sit.