Most people would probably be more concerned about taking out a feral dog or venomous snake vs. muzzle blast. No?
It is part of the equation, as there are lots of both.
My FIL was already deaf in one ear and hard of hearing in the other and he thought the .327FM was painfully loud when shot outdoors. He was anot a "gun guy" and I wished he had consulted me before he bought it. I would have suggested a .38spl, K or J frame.
Besides, I think the "main competition" for the .327 is .38/.357 or centerfire automatics in the 9mm or larger range. I doubt any of them would qualify as "no hearing protection needed" if someone knew he was going to discharge the gun. For that matter, hearing protection is recommended when shooting any firearm in any caliber.
Nowadays, no firearm without a suppressor qualifies as "no hearing protection needed"
if you are shooting for pleasure. But he was not shooting for pleasure, he was shooting venomous snakes near his and neighbors houses and feral dogs in his neighborhood. Kids nearby out & about. Running back inside for a set of muffs not a viable course of action, the varmint needs killing RFN. The 80YO man was already toting the SP101 on his belt with some cartridges in his pocket, a wallet, cell phone, keys, etc.
SAAMI max (except .38spl tgt HBWC from reloading manuals)
Code:
- CARTRIDGE - SAAMI MAX -
.38 Short Colt 07,500 CUP
.38 Long Colt 12,000 CUP
.38 S&W 14,500 PSI
.38 S&W Special 17,000 PSI
.38 Special +P 20,000 PSI
.380 ACP 21,500 PSI
9×19mm Parabellum 39,200 PSI
9×18mm Makarov 23,206 PSI
.38 Super 36,500 PSI
.357 Magnum 35,000 PSI
.357 SIG 40,000 PSI
.327 Federal Magnum 45,000 PSI
.454 Casull 65,000 PSI
.38 S&W Special TGT HBWC 11-14,000 PSI
After my FIL complained, I looked up the .327FM and figured he was likely right in that its muzzle blast was exceptionally loud. More than 3x the PSI of .38spl tgt HBWC, More than 2x .38spl and .38spl +P. 1.3x .357mag.
And it exceeds .357Sig in max PSI. .357Sig--the cartridge that folks at the IDPA club I shoot warn everyone to double-check their earpro before the .357Sig shooter starts his stage.
He also had to take into account his "snake alarm" dog, who considered it her sworn duty to find snakes in the vicinity and bark up a storm until they were attended to. She was nearby and dogs don;t do earpro.
As you said, the .327 can always be down-powered with .32 S&W long and .32 H&R. I've fired both of those out of my .327's with 4" and 5&1/2" barrels and found them to be no worse than .38 special out of comparable frames.
That is what kept my FIL from selling it off. I ordered and had sent to him three different boxes of .32 Long and suggested he start with the 100gr HBWC. Those did the trick. Killed rattlers, cottonmouths, and feral dogs well enough. (Non-venomous snakes got a pass and nice strays got adopted.)
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I don't dislike the .32FM, I just think that it takes a whole lot more pressure & blast to do what .38spl and .357mag already do.
I think .32FM's biggest selling point is making available a platform in which to shoot .32Long 100gr HBWC, for a package that recoils even less than .38spl 148gr HBWC.