.300 BLK Non-Suppressed Sound Levels

[NavArch]

What sort of sound levels should a person expect from a non-suppressed 16" .300 BLK carbine? All I can picture in my mind is a frequency somewhat lower than 5.56 and dB level less than .308, but that is still a pretty large ballpark.

[rsilvers]

I don't have our testing handy, but I found another maker say that with 220 grain, they got 155 dB unsuppressed for a 16 inch rifle. Not sure about other ammo.

5.56mm is about 165-168 dB.

So that is like having a 10dB silencer.

[NavArch]

I don't have our testing handy, but I found another maker say that with 220 grain, they got 155 dB unsuppressed for a 16 inch rifle. Not sure about other ammo.

5.56mm is about 165-168 dB.

So that is like having a 10dB silencer.

First, thanks for taking the time to reply. Sitting here on my butt, following surgery, I know your days are busier than mine.

Second, I just checked on AAC's physical location. Good ol' "Larryville", as those of us in Suwanee used to say.

Third, the advertized topic: Without further data, my first guess is that one of the significant reasons for the reduction in sound level between 5.56 and the 220gr .300 BLK may be simply that the 220gr round is subsonic, and the ranges at which I would use .300 BLK would definitely be inside the range at which 5.56 goes subsonic.

Interesting logic loops I find myself in. Every time I decide that the family's next AR should be a 5.56, I find very enticing data on .300 BLK that pulls me the other way: .300 BLK the definite winner in the KE race, and only marginally less flat a trajectory inside 200 yd.

[rsilvers]

If you use QuickLoad, you can see that 300 BLK has lower muzzle exit pressure - even with full power ammo. Less powder and larger bore. This is the same reason why it needs a pistol or carbine gas system, rather than a carbine or mid-length gas system - the pressure drops off faster.

[NavArch]

Another factor would seem to be the predominant frequency of muzzle blast, some being more piercing (pardon the pun), and carrying further, than others. Has that been your experience, or is my thought pattern simply wrong here?

[rsilvers]

Lower frequencies carry farther, but gun shot noise is broadband and pretty much all frequencies - which is why the wave-cancellation theory of some silencers never actually worked.