40 S&W Ruger PC Carbine

[@thewheels]

So, I'm losing hope and willpower to hold out for the Ruger carbine in 357 Sig or 10mm and I'm reading through the manual to make sure I'm not missing any important tips/facts and stumble across this statement:

Note that the use of aluminum case ammunition with the
PC CARBINE™ chambered in 40 S&W is strictly prohibited.

I checked the section on the 9mm version and there's no mention of any limitation on case material.

So...what gives? Why only brass and steel in the 40 s&w?

 

[dsdmmat]

Who knows? I wouldn’t shoot steel cases in anything but a foreign battle rifle. Maybe Ruger is worried about the aluminum cases leaving metal residue in the chamber.

you can always grab another barrel and chamber it for 357 sig.

 

[Deplorable Me]

From a metallurgical stand point, aluminum is harder than brass. Maybe it's a wear and tear issue? I only run brass through my handguns for that reason (the auto loaders.) Steel cases drive me crazy, just don't seem right. IIRC the .40 is a higher pressure cartridge than the 9mm. Brass is more malleable than aluminum, this is what allows brass cases to be reloaded (the ability to flex a few times). All chamber tolerances are not the same, maybe Ruger is concerned about case rupture with the aluminum vs the brass. (This is my best guess, better assumptions and guesses after 3 beers.)

 

[Deplorable Me]

Who knows? I wouldn’t shoot steel cases in anything but a foreign battle rifle. Maybe Ruger is worried about the aluminum cases leaving metal residue in the chamber.

you can always grab another barrel and chamber it for 357 sig.

Yes, add that. Steel cases sometimes have a polymer coating. I could see it cooking off when hot and gumming up a chamber. Extractors on battle rifles may be more robust than a Ruger house rifle.

 

[@thewheels]

According to the manual, they don't mind steel cased.

The RUGER® PC CARBINE™ chambered in 40 S&W caliber is designed to
properly function with factory loaded brass or steel-cased standard pressure
ammunition manufactured to U.S. industry standards.

I've been looking for somebody that could do another barrel chambered in 357 Sig online and haven't had much luck.

 

[@thewheels]

Also, max pressure on the 40 s&w is 35,000 psi while the 357 Sig is 40,000 psi.
I'm not sure an extra power recoil spring will make enough difference there?

 

[Phauxtoe]

it may be a Supported vs Unsupported Chamber thing.
any gunsmiths in here?