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Caliber equivalency (sort of)

nonameisgood

Regular Member
Joined
Dec 4, 2008
Messages
1,008
Location
Big D
I think we have a bit of confusion:
The .38 series all use approximately the same diameter bullets, and approximately isn't good enough. At the tolerances provided in modern guns with jacketed bullets, 1/1000 of an inch is huge.
9mm, .38 Special, .357 Sig, .357 Magnum, .357 Max, .380 ACP, .38 Super all have different cases and very different charges behind the bullet. Firearms manufacturers try to make it so we cannot chamber and fire the wrong round, but us idiots are clever.

357 Mag is in every way identical to .38 Special, except overall length and, more importantly, chamber pressure. The overall length _should_ prevent one from putting 357 Mag in a .38 Spec revolver.

And because a round seems to fit a chamber does not mean it is safe...

SAAMI is the keeper of the data for the maximum pressure behind each bullet and the associated dimensions.

Please do not attempt to do what we have all done by accident. I once "tried" to run a Walther P99c 9mm mag thru my HK P2000sk 357 Sig, which didn't quite work. The 9mm case is sitting on my nightstand as a reminder to not do that again.

A friend of mine (very smart PhD type) still gets confused about which ammo is which. He knows his decimal fractions well enough that he doesn't get the 38/380 nuance. And it is all about nuance.
 

rodbender

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Jun 23, 2008
Messages
2,519
Location
Navasota, Texas, USA
You can shoot a .45 Long out of a .44 Magnum.
http://herohog.com/images/guns/ammo/

No, a .45 is .454 or .451 and the .44 Mag is .429

Ruger once made a SA that had interchangable cylinders, one was for .357 Mag. (.357), the other was 9MM Luger (.355). The barrel was actually bored and grooved for a .357 Mag. which is .002 bigger than the 9MM. They understood that boring and grooving the barrel for the 9MM would not work.
 
Last edited:

tcmech

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Aug 2, 2009
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No, a .45 is .454 or .451 and the .44 Mag is .429

Ruger once made a SA that had interchangable cylinders, one was for .357 Mag. (.357), the other was 9MM Luger (.355). The barrel was actually bored and grooved for a .357 Mag. which is .002 bigger than the 9MM. They understood that boring and grooving the barrel for the 9MM would not work.

Ruger made that gun for a long time and I believe they still do. I have one that was made in the early 70's.

The 7mm ruger / luger round that is being referenced by the OP is probably chambered in 7.65 browning. I believe this is a 32 acp. I could be wrong about that as I am not looking at any of my reloading manuals at the moment.

The smartest thing to do with a gun if you are unsure if the ammo / gun combination is safe is to just not shoot it.
 
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