Question on fully supported chambers

[Lugnut]

Now that I'm starting to reload I've started to look into the warnings of using .40 S&W in gun without "fully supported chambers for cartridges". I hear so much crap about Glocks but when I compared my Sig 229 barrel to my Glock 27 barrel- I could see NO difference in the support of the cartridge. I've seen some pics via searches that show unsupported cartridges but it appear to me that both Glock and Sigs (at least newer ones) fully support the cartridge. Am I missing something here?

I've successfully tested various .40 S&W loads in my Sig and no want to start using reloads in my Glocks as well. Anything I really need to be concerned with?

Thanks!

 

[jhrosier]

The feed ramp on the Glock extends a little further into the chamber and I've heard the the chamber diameter on the glocks is larger than many others. (The .40 is more of an issue because it operates in the "+P" range.)
The somewhat lesser support is said to cause the base of the cartridge to expand enough to promote early case failures. Some folks refuse to reload any .40 brass which has been fired in a Glock.
I wouldn't agonize over it, but it's probably a strong case for moderate handloads.

 

[jhrosier]

BTW, you are aware that lead (non jacketed) bullets in the Glock is a major no-no?

 

[Lugnut]

The feed ramp on the Glock extends a little further into the chamber and I've heard the the chamber diameter on the glocks is larger than many others. (The .40 is more of an issue because it operates in the "+P" range.)
The somewhat lesser support is said to cause the base of the cartridge to expand enough to promote early case failures. Some folks refuse to reload any .40 brass which has been fired in a Glock.
I wouldn't agonize over it, but it's probably a strong case for moderate handloads.

I have noticed that the Glock chambers tend to have slightly more "play" or room in them. But I honestly can't see any place near the ramp that is unsupported... no less supported than my Sigs anyway.

I've never used straight lead bullets in any of my guns.

 

[EddieCoyle]

Lugnut,

Looked at the brass fired from your Glock vs. new or range pickup brass that did not come from a Glock. You'll notice a prominent bulge on one side of the case where the brass expanded into the feed ramp area.

You should be able to see it on the .40, it's quite noticeable (and disturbing) with the 10mm. I'm probably going to get an after market barrel for it.

 

[Lugnut]

Lugnut,

Looked at the brass fired from your Glock vs. new or range pickup brass that did not come from a Glock. You'll notice a prominent bulge on one side of the case where the brass expanded into the feed ramp area.

You should be able to see it on the .40, it's quite noticeable (and disturbing) with the 10mm. I'm probably going to get an after market barrel for it.

Eddie- I'm no expert here but here's what I did. I gave my Glock barrels and my my Sig barrels a good looking over. I honestly could not see any area of the case that was unsupported with the Glock barrels relative to the Sig barrels. However... I've been told that the Glock barrels are not as tight- hence Glock cases tend to have a bigger buldge. Eitherway I'll still relaod it.. I'll just make sure to inpect it well beforehand.

 

[Lugnut]

OK. I think I understand what "UNSUPPORTED" really means now. Here is something from Lyman:

"If the distance from the cartridge's headspacing surface to the matching chamber surface is too great, the cartridge/firearm system is said to have excessive headspace. When this condition is present, the case is inadequately supported by the chamber and the cartridge may stretch excessively, split, or burst, upon firing."

So with this definition I guess an inadequately supported case could be because of excessive clearance OR an area of the case that is not surrounded by a chamber. I think with Glock's, the issue is excessive clearance- hence the bulging cases compared to other firearms. If I look at the Glock chambers it fully surrounds the case.. but with excessive clearances. FWIW I also notice slight buldges in many of my sig cases as well, just not as severe.