How important is chamber support? (320/Glock/Beretta)

[APena]

How important is chamber support? The other day I was comparing several different pistols and there was a SURPRISING difference between the three I was looking at. This is my first post so I apologize ahead of time if the pictures don't upload correctly.


The Beretta literally swallows the entire case, the AAC Glock barrel seems fine..... but looking at the 320 barrel has me scratching my head a bit, it appears at LEAST a 3rd of the case is sticking out of the barrel. It's also a little strange that the 320 is the only one that will scrape the case head against the breech face of the slide when locking up. I have 3 sig 320s FYI and they all do this and have the same case exposure. SO, case support not a big deal or does the sig look like a case failure waiting to happen?

Again apologies if the pics don't load correctly as the post won't be nearly as interesting, and also all the guns run fine supported or otherwise, just curious about it and wondered if anyone else has noticed this?

[Alpha Sierra]

This is a worry, why?

[APena]

I wouldn't say its a worry per se, just random fact that is interesting to me as a gun nerd. HOWEVER when something is different then the rest I like to know WHY its was done and if its a good thing or not.... for instance I "hear" people complain about the 320 having issues with lock up being really tight or not going into battery.... if the case is tight enough that its dragging across the bolt face THIS is likely why some people have noticed this or seem to have more issues with that particular design than with others (something the rest my pistols don't do that all 3 of the 320s do actually do)

As to the AMOUNT of case sticking out could cause a higher rate of case failures...this was an "issue" with some Glocks in the past as I understand causing the nicknamed KaBooms etc and of course people getting after market barrels for their 10mm Glocks for the full support of hot loads. BUT I haven't heard of this topic as of late, but seeing the amount of case sticking out of the 320 chamber I am now curious if all the past "issues" of chamber support in other guns was mostly conjecture or if the 320 is just a model you would avoid running reloads in....

PERSONALLY I have decided to NOT run anything but new manufactured ammo in the 320... based of how the round sits but that's based on nothing other then me making observations off what I'm seeing, and wondering if others have seen and came to the same conclusion or maybe as I mentioned, case support not being the big deal it once was thought to be.

[olstyn]

This is a worry, why?

Mostly because of how Glocks in .40 S&W used to be. The 320 at least makes me raise an eyebrow in the direction of SIG. It might not be unsafe with in-spec standard pressure ammo, but it sure looks like a situation that leaves less margin for error with loads at the top of the range and/or sketchy/flawed brass than a lot of other pistol chambers.

[Rack]

That first picture of the 320 barrel would worry me.

[Alpha Sierra]

That first picture of the 320 barrel would worry me.

Does it worry you in Glocks?

[arcfide]

As a point of reference, you can see a progression of how Beretta has been handling this in their 9mm's over the decades. There's a thread somewhere here with photos of the Beretta APX, Px4, and 92's chamber support. These are all from the same manufacturer, with different actions, and they all show different levels of chamber support. The APX shows much less chamber support than the Px4 or the 92, and some people have been talking about that as an issue, but at least, with the exception of a few apparently isolated or not very reproducible results, this doesn't seem to negatively affect reliability when it comes to kabooms.

[echo5charlie]

The following came into my shop all within the past 2 years. One was an Ultramax round (XDS), one an unknown "buddy reload"(FN FNP), and one surplus round (Taurus 709).



The 709 would have not had an issue at all but the chamber support is basically a joke. The customer brought in the remaining Metallverken rounds and I fired them from my Beretta M9 with no issue. The rounds were intended for Luger pistols and submachine guns....back in the 1960's.

My opinion on chamber support is this: use quality factory ammo and stay away from reloads, reman, and surplus.

[APena]

The following came into my shop all within the past 2 years. One was an Ultramax round (XDS), one an unknown "buddy reload"(FN FNP), and one surplus round (Taurus 709).



The 709 would have not had an issue at all but the chamber support is basically a joke. The customer brought in the remaining Metallverken rounds and I fired them from my Beretta M9 with no issue. The rounds were intended for Luger pistols and submachine guns....back in the 1960's.

My opinion on chamber support is this: use quality factory ammo and stay away from reloads, reman, and surplus.

wow that pretty much confirms my thoughts on the matter and as you stated have decided to keep only new manufactured munitions in the arms that lack support... That being said I wonder why arms companies would choose to do that? wouldn't cost them any money to have the case insert a little further, and in the sigs case I'm unsure how much MORE reliable having only 2/3 the case have to insert into the chamber then the whole thing....

Many thanks for the first hand data points with pics!

[mmc45414]

Mostly because of how Glocks in .40 S&W used to be.

And I believe the .40 is also thinner at that part of the case. When I was reloading a lot of .40 I used light charges of slow powders and light bullets to create a longer pressure curve in a larger capacity case. For a variety of reasons I have like most folks moved over to 9mm, and while I would say this was not necessarily one of the reasons, it is one of the reasons I am kinda glad I have.