Reloading Question- 'Unsupported Chamber' in 40 S&W?

[superduty]

I'm doing a little reading about reloading .40 S&W, and there are warnings in the Hodgdon Manual about only loading for those firearms that fully support the cartridge in the chamber.

 

I've seen mentions of supported vs. unsupported chambers in my light research on various forums as well.  I'm a little confused though-  what exactly is a supported vs. unsupported chamber?

 

Is there more to it than a .40 cal is a .40 cal?

 

 

[BigK]

From what I've read/heard, it's most common with Glocks. The rear of the cartridge doesn't go all the way into the chamber, leaving that end of the brass unsupported by the barrel chamber. When the round I'd fired the pressure bulges the rear of the brass out just forward of the rim on the part hanging out off the chamber. This stresses the metal making it thinner. Many sizing dies won't remove this bulge, because it's so low on the brass. Even if you buy a fire that removes the bulge, the metal is already weakened. Edited September 27, 2015 by BigK

[Raoul]

IIRC this mostly concerns the chambering of the .40 in Glock pistols. 

The factory Glock barrel doesn't fully surround the case.

 

 

You can usually spot a .40 casing from a Glock due to a bulging case.

Infamously referred to as the Glock smile.

[RED333]

These are extreme cases, got these in some range pick up.

[URL=http://s896.photobucket.com/user/redintn/media/Glock%20smile/gs1_zps79f1ca0f.jpg.html][/URL]

[URL=http://s896.photobucket.com/user/redintn/media/Glock%20smile/gs2_zps897a7b30.jpg.html][/URL]

[superduty]

_{Great, thanks for the clarification folks!}

[Omega]

When I first started reloading in the mid 80's, I never heard of this so I reloaded for my G23, even with (gasp) lead bullets.  I never had any issues with any of my rounds once I got the OAL correct.  The trick is to cull any cases that have any issues, smiles, cracks or bad bulges.  

[gregintenn]

These are extreme cases, got these in some range pick up.

That doesn't seem good at all! :ugh:

[battleop]

I think somewhere around the late 90s Glock made a change to the barrel design that eliminated the the Glock smile. I have a 3rd Gen 22 that does not create Glock smiles.

[hipower]

I think somewhere around the late 90s Glock made a change to the barrel design that eliminated the the Glock smile. I have a 3rd Gen 22 that does not create Glock smiles.

 

Far as I know, you are right on this. Never any issues with any of the Gen 3 40 pistols I shoot. That's a G22 and a G24.

[deafdogdief]

Feed ramp was pulled to back of the chamber when Gen 3 came out from what I have researched.
This isn't just about Glock. More of them in circulation so problem is more likely to be blamed on them. Isn't just .40, isn't just Glock.

[Grunt67]

 The Lee Bulge Buster kit will take it out, along with the Lee carbide sizer die. It pushes the brass up thru the die & sizes the

entire cae. I've done a big bunch of them that way. Had no issues.

Redding also make a die for it. More expensive than Lee but does the same job.

The Lee unit also has a hopper on top that collects the brass as it comes thru. Rather neat.

[Grunt67]

 The Lee Bulge Buster kit will take it out, along with the Lee carbide sizer die. It pushes the brass up thru the die & sizes the

entire cae. I've done a big bunch of them that way. Had no issues.

Redding also make a die for it. More expensive than Lee but does the same job.

The Lee unit also has a hopper on top that collects the brass as it comes thru. Rather neat.

 

This was with older Glock 22s. Have no experience with later versions. Thankfully, I sold mine & bought a Walther PPQ.

[bulm540]

A must if you shoot USPSA with heavy bullets and fast powders in limited division.