glock 31c question?

[jethrothefireman]

Im really glock illiterate.
Buddy has come across this gun it says .357 on the gun and clips but it has an aftermarket barrel.  He was told it was a 40 Cal. barrel a 40 wouldnt fit in a 357 barrel right.  The barrel isnt stamped.   

[Savage]

jethro,
The .357 Sig is a .40 S&W case necked down to accomidate a .355 dia bullet. It should be easy enough to check the bore size to deterime what caliber he has. These pistols are easily converted back and forth by a simple barrel change. The magazines will work with either round, and barrels are inexpensive. The Lone Wolf barrels are the best I've used for the money! A word of caution, a .357 Sig round will chamber and fire  in a .40 barrel. A certain case failure will occur. It would be wise to have someone knowledgeable check it out before firing!  Enjoy the pistol!!
Savage

[jethrothefireman]

Thanks for posting, we figured out the bullet thing it has a 40 cal barrel in it.  Now the thing is jambing terrible about three time in a mag. I think its the mag spring any suggestions?

[Savage]

Try another magazine. You didn't say what kind of malfunctions you were having, that would be helpful.

[pastorp]

Savage, why would firing a 357sig round in a 40s&w barrel cause a certain case failure. I would agree it would be unsafe to reverse this but don't agree it would be unsafe to fire the 357 in the 40 barrel.

I've fireformed too much brass to buy this statement. Regards, Byron

[Savage]

Maybe I made it sound worse than it is! The .357 case with it's smaller neck dia. would at best fire-form the case to the chamber. The case failures I'm referring to would be case neck splits. This is all assuming the extractor holds the case head against the breach face preventing an excessive head-space condition. The latter condition would result in case head failure, and possible damage to the gun with injuries.
Savage
FWIW: A .40 S&W round will not chamber in a .357 Sig barrel.

[GSD17]

MOST GLOCK errors are brought on my shooter error or magazines needing care.