308 Suppressor design - Subsonic vs. Supersonic

[MMH]

Would a suppressor designed specifically for subsonic loads be different than one designed for full power supersonic? How quiet is possible for a subsonic. I know not to expect hollywood quiet, but what is reasonable?

[Enfield577]

I would suggest yes

I have made a few cans for sub sonic 22, 32 and 9mm. I have made K baffles for these and they are Hollywood quiet (search my old posts)

Ks however don't work so good on high velocity

[govtcontact]

Sorry for jumping in for my first post.

Some time ago I ran across US Patent #3,478,874 (Nov, 1969) titled "Silencer For Firearms Discharging Gasses At Supersonic Velocity".

The beauty is in the super-simple design...Just two surfaces to reflect the sound waves out of phase.

[Scared_of_zombies]

Assuming a fixed volume, yes. K's are much better for lower pressure's (Subs only) while 60 degree cones will be MUCH more optimal for the higher pressures and volume of gas from using a full power .308.

[DanielWilson]

Many of the commercial cans are reported to reduce the sound by 24-32 decibels. That's about the same reduction rating of a pair of ear muffs.

I got to shoot a .308 with a commercial can a few days ago. It was much quieter with the can than without. I took one shot with an ear plug out. It was a little uncomfortable, but not painful like it would be unsuppressed.

Our shooting was with supersonic ammo. My load was 165 grains ... believed to be about 2700 fps. We didn't have any subsonic with us that day.

[MMH]

What is the approximate angle on the K's?

Assuming a fixed volume, yes. K's are much better for lower pressure's (Subs only) while 60 degree cones will be MUCH more optimal for the higher pressures and volume of gas from using a full power .308.