how quiet can you get a whisper

[rockman]

Originally Posted by Rikky Lee

Speed of sound at 14 deg Celsius is 1114 fps. Beg, borrow or steal a chrony and see what velocity you are getting. I found good accuracy at 1100 fps but aim for 1050fps as a rule of thumb.

that sounds like good advise. It could be that im sitting to close to the speed of sound.will try to arrange a chrony.thanks.

[SgtCottle]

N110 and N130 both seemed a little louder than other powders that I have tried. I don't know what is available to you, but it seems that I have had my best results with Alliant 2400 and Accurate 1680.

[Expatriot]

Two things are gonna make a big difference in the sound level with subsonics.

Powder selection. Small charges of fast burning powder will be much quieter than bigger charges of slower burning powder. I have found the Vhitavuori powders to be very quiet.

The baffle design in the silencer is critical too. Baffles meant to work high pressure gas will not be nearly so good with a low pressure system like a subsonic 300 W.

The best baffles for low pressure systems are long stepped cones with a shear cut at the apex.