It'll be down the the moderators used in each case. I've shot my Sak modded HMR against a fairly short barreled Blazer .223 ( I forget which mod he was using) and the two were indistinguishable. We were shooting rabbits and foxes at night from a pick-up and from inside the cab you couldn't tell which rifle had fired.
Basically, for a rimfire the HMR makes a considerable crack because of the speed, and you can't moderate that. Any supersonic bullet is going to produce a whip crack and once modded there's very little in it between a the sonic crack of .17 HMR and and that of a small .22 cf. Different story with larger calibres. A moderated .243 (to my ears at least) produces a noticeably more strident crack than a .222/.223 or a Hornet. 5.5mm cartridge. With the right moderator a Hornet will be no louder than an HMR.
Basically, for a rimfire the HMR makes a considerable crack because of the speed, and you can't moderate that. Any supersonic bullet is going to produce a whip crack and once modded there's very little in it between a the sonic crack of .17 HMR and and that of a small .22 cf. Different story with larger calibres. A moderated .243 (to my ears at least) produces a noticeably more strident crack than a .222/.223 or a Hornet. 5.5mm cartridge. With the right moderator a Hornet will be no louder than an HMR.
