>>The difference is, .22 (target long rifle rounds) and .45 are BOTH sub sonic.
That’s a similarity, not a difference. Yet the 45 is unsurprisingly much louder because of the much greater energy.
>> Youd be surprised.
Actually, I wouldn’t be.
No, standard velocity .22 is slightly supersonic, at least in a rifle: http://en.wikipedia.org/wiki/.22_Long_Rifle#Standard_velocity.
There are ones specifically loaded to be subsonic: http://en.wikipedia.org/wiki/.22_Long_Rifle#Subsonic.
I’m still willing to say that the action cycling will still make more noise than the round.
The .45 has a much greater release of gas. Both are probably subsonic. Imagine stifling a tiny fart and a gigantic fart.