RKI: Convert 9mm to SIG 357?

[robmac]

Got a custom Glock 17 with the Stainless Schuemann Hybrid Barrel, in 9mm of course and I want to convert that barrel to .357 Sig. Same frame - right? Same 0.355" dia bullet - right? Schuemann is a stronger steel - right? The hybrid ports on top of the barrel markedly reduce barrel pressure - right? So don't I just have to ream the chamber?

[robmac]

A pic

[Wadman]

Hey Rob,

That's a heck of a setup there.

While the bore diameter of the .357 Sig is indeed .355, the rest of the cartridge is based on the 40 S&W. It's a lot more common for a 40 S&W to be interchangeable with the .357 Sig. I don't thing it's a question of steel strength but rather slide weight.

[BUFF]

There are other considerations, such as magazines, bolt face, extractor and ejector.

Start with a .40 pistol.

[FN74]

Ditto - start with a .40 cal pistol - don't butcher that 9mm..

[Wadman]

Originally posted by BUFF
There are other considerations, such as magazines, bolt face, extractor and ejector.

Start with a .40 pistol.

Geez, I forgot about all that stuff. I'm slipping.

[robmac]

9mm/.40 frame are the same - Mags are interchangeable....bolt face will be a toughie! Not so a new extractor. Slide is Capsian bar stock stainless - so maybe they can do the bolt face.....hmmmm

Pic of the whole pistol:

[FN74]

What frame do you have? Does it have one or two pins above the trigger? If it has one, do not use it for a .357 sig or .40 round, it will not hold up, which is the reason glock added the second pin in the frames in the firstplace.

Personally, I'd buy a new or used glock in .40 and work it up from there, much cheaper in the long run.

You'd need a new ejector, extractor, bolt face remilled. You'd need to use .40 cal mags in it as well, the feed lips on the 9mm and .40 are differant.

give me a shout if you want to chat about it - I've been certified on glocks for 7 years now.
Regards,
FN74

[renaissance_warrior]

Ok, here's my opportunity to open myself up for some ridicule. Regarding the gas vents, wouldn't the escape of the gases that soon into the combustion process cause a distinct loss of velocity?

Looking at where the first gas relief hole is, it would appear that the powder in the case wouldn't have even burned completely by then. Just curious.

Mark :beer:

[robmac]

Originally posted by renaissance_warrior
Ok, here's my opportunity to open myself up for some ridicule. Regarding the gas vents, wouldn't the escape of the gases that soon into the combustion process cause a distinct loss of velocity?

Looking at where the first gas relief hole is, it would appear that the powder in the case wouldn't have even burned completely by then. Just curious.

Mark :beer:

Mark: You are quite correct - hence my desire to make the conversion. The recoil spring in the top photo was replaced with a standard glock guide rod and I have worked the spring down from the standard Glock spring rate (17#? down to probably 1/2 of that). So now it lazily cycles with standard 9mm ammo, better with +P hotter ammo. I already have another GL17, and wanted to do something with this GL17 without changing the whole thing so I could retain all of these WONDER-PARTS. Just for the record, I bought it like this at a gun show, and been tinkering with it from time-to-time. Does it make any sense? - NO! But neither do most of these GUN-toys - but let's all enjoy them just the same.

FN74 - I will call you.