Ed Harris
posted this
18 March 2008
miestro_jerry wrote: I shoot a lot of subsonics in my 10/22T rifle, it really isn't that quiet. My middle son has a Ruger pistol that has an integrated Arc Angel, and that pistol is quiet, but you still hear it, none of this TV whizzing past with no noise.
Lower noise signature requires:
1) use of a fast burning powder, and
2) using minimum charge weight to ensure reliable bullet muzzle exit consistent with acceptable projectile stability, and
3) a long enough barrel to provide sufficient expansion ratio to ensure that the bullet is no longer accelerating, but has begun to “slow down," so that there is low muzzle exit pressure.
Eliminating the super-sonic “crack" the bullet makes when passing a nearby object only requires the bullet be subsonic. But lowest noise signature requires you drop projectile veloicity farther below that, to ensure that exit velocity of propellant gases at the muzzle will be subsonic also.
There is about a 10dB drop in the noise level of .38 Special or .45 ACP ammunition fired from a 24 inch or longer rifle length barrel muzzle, when the velocity of the handgun ammunition when fired from the rifle is reduced from about 1050-1080 fps to a lower level well below 900 fps.
While you will not get the movie “pffffff!" You can reduce the measured peak pressure decibel levels enough that they start blending in with suburban background noise, so it is much less noticeable, doesn't carry as far and won't disturb the neighbors.
The factory-produced recipe is to use .38 Special midrange wadcuters or to handload cast lead bullets with not more than about 3 grs. of fast burning powder such as Bullseye in the Marlin Cowboy II or rifle with 24 inch or longer barrel. Keep the rifle velocity of the handgun ammo when fired in the rifle less than about 900 fps and its noise level is almost like shooting standard velocity .22 LR from a 20” sporting rifle.
Not “quiet” but certainly mild and it remains accurate and effective.
73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia