What is louder!

MXoutdoors

MXoutdoors

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Not sure if their is any info on this or if this is the place to ask, but what would be more harder on the ears. A 22-250 firing a 40gr v-max @ 4000ft/s or a .243 firing a 65 v-max @ 3500ft/s. Both loads would be shot out of a bolt action with a 22" barrel. Thanks for any info

Ron
 
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MXoutdoors said:
Not sure if their is any info on this or if this is the place to ask, but what would be more harder on the ears. A 22-250 firing a 40gr v-max @ 4000ft/s or a .243 firing a 65 v-max @ 3500ft/s. Both loads would be shot out of a bolt action with a 22" barrel. Thanks for any info

Ron
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Given equal barrel lengths, the cartridge with the greater powder charge produces the greater blast, but the smaller the bore diameter, the sharper the sound. Thus, choosing a heavier bullet, with the same powder, can reduce the blast due to the smaller charge. The boom from my 20" .375 Ultra when I ignite 100 grs of powder is quite pleasing actually, but the sharp crack when shooting a 55 gr BT with a case full of Varget in my .243 is less pleasant.
 
Given equal barrel lengths, the cartridge with the greater powder charge produces the greater blast, but the smaller the bore diameter, the sharper the sound. Thus, choosing a heavier bullet, with the same powder, can reduce the blast due to the smaller charge. The boom from my 20" .375 Ultra when I ignite 100 grs of powder is quite pleasing actually, but the sharp crack when shooting a 55 gr BT with a case full of Varget in my .243 is less pleasant.
Click to expand...

This is likely a function of the frequency mix of the muzzle blast rather than any actual change in the sound pressure level. We perceive low frequency sounds to be quieter than high frequency sounds.

I have sound tested a variety of different firearms in different calibers. A 5.56mm short barreled carbine will produce almost exactly the same SPL as a conventional .308 rifle. The sound meter doesn't distinguish frequency, only the overal peak of the sound event.

As an example, most people will perceive a 45 ACP to be quieter than a 9mm when in fact the sound meter shows the opposite to be true. The 45 produces a pleasant low frequency sound where the 9mm is a more high pitched event.
 
It depends on the residual pressure (and volume of gas) in the barrel when the bullet exits, and the size of the bore.

Large bore + low pressure = moderate low frequency sound pressure, as in a 45 ACP.
 
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