The legend of the Glock 40 caliber kBoom

[TedBeau]

I just got my Glock 27 in 40 caliber. I have seen a few references to the 40 caliber Glock barrel not fully supporting the case and having a tendancy to go KaBoom if its a Reload/+P/Other cause.

There is even mention of it on the Buffalo Bore web site for their 40 Cal +P.

There is such a variety of 40 S&W pistols in public use that we will not determine what pistols are compatible with which 40 S&W +P loads - this is your responsibility! We will add that this ammo is safe in pistols that use a fully supported chamber. Please read the safety notices below. The first one is taken form the Speer #13 loading manual. The second is taken from Hodgdons #27 loading manual.

SAFETY NOTICE

"Some pistols chambered for the 40 S&W cartridge may not provide complete support of the case head. If this condition exists, normal pressure loads such as those shown here can cause the case wall to bulge or rupture at the unsupported point. Contact your firearm manufacturer to determine if your pistol completely supports the case head, or ask a gunsmith to inspect your pistol before using it with ANY ammunition. It is the gun owners responsibility to know his firearm and its capabilities and limitations."

40 S&W WARNING

"This data is intended for use in firearms which fully support the cartridge in the chamber. Use of this data in firearms which do not fully support the cartridge may result in bulged cases, ruptured cases, case head separation, or other conditions which may result in damage to the firearm and/or result in injury or death of the shooter or bystanders."

Glock happens to chamber their 40 S&W pistols without a fully supported chamber and both of those above safety notices are likely aimed at Glock. I know of no other 40 S&W handguns being sold in the US that don't have fully supported chambers. If you really want to shoot our 40S&W ammo in your Glock, have an after market barrel that uses a supported chamber, dropped into it. This is a fairly common practice and will give you the safety margin needed to fire our ammo in your Glock. It will also likely give you more velocity than the factory Glock barrel. I personally own two Glock Model 23's. Both of mine are going to get after market barrels dropped in so that I can use this excellent ammo in them.

So the question is, is this something that I need to be concerned with since my Glock is new? It's not a Gen 4 because they are not making the 27 in Gen 4 yet.

Is this an internet legend or is there something to this? Can I shoot +P ammo out of my Glock or not?

[DefensiveCarry.com]

[glockman10mm]

I do not think there has been a designation for a +p 40 round by SAAMI. To answer your question, yes there were isolated cases of this in the 40 glocks, but it has usually been attributed to issues other than over pressure rounds. As part of the design that contributes to the glocks reliability, the chambers are built to a more loose tolerance to enhance feeding and extracting under dirty conditions.

These issues were addressed, and myself and thousands of other LEOs shoot thousands of rounds thru our 40s every year with no issues. We trust them, and you can too.

[Ragin Cajun]

Why do you want to shoot ammo that is not in the Sammi specs for a gun you just bought? Maybe you should have bought a 10MM instead. If you shoot ammo that was designed for the gun, you won't have any issues. The whole Kaboo thing got blown way out of proportion on the internet. You only need to be conserned if you shoot reloads or "+P" ammo, both of which your manual tells you not to shoot. Many people shoot reloads out of glocks, including myself but I don't over do it on my loads.

[Sleipnir]

Gen 3 Glocks did away with the unsupported chamber, but if it's really a concern for you then buy a Lone Wolf drop in barrel.

[HiFreq47]

Gen 3 Glocks did away with the unsupported chamber, but if it's really a concern for you then buy a Lone Wolf drop in barrel.

No they did not, my Gen 3 G19 and both of my Gen 3 G23s have chambers that aren't fully supported.

OP, don't worry about. The problem is ammo related, not gun related.

[10thmtn]

There is no such thing as a "fully supported chamber" in ANY pistol.

In order for the extractor to grab the case rim, there has to be some part of the rear of the case that is not enclosed by the chamber. This area is "unsupported."

As mentioned, Glock erred on the side of reliable feeding and extraction in their chamber design. Use quality factory ammo, and you should have no issues. If you want to shoot reloads or overpressure ammo, get an aftermarket barrel that has more support - but it will still leave some portion of the case "unsupported."

There is no SAAMI spec for .40 "+P" ammo. You use that ammo at your own risk - and it WILL void your warranty.

[tokerblue]

I agree with the others. Don't use .40 "+P" or reloaded ammunition with the Glock 27. You don't need it since the round is already quite hot as is.

[ASSA9]

Gen 3 Glocks did away with the unsupported chamber, but if it's really a concern for you then buy a Lone Wolf drop in barrel.

This was my understanding as well
My Gen 3 G26 looks like every other MFGs chamber
To the OP
If you have any doubt about yours just Goggle "supported VS. unsupported + Glock "and look for photos .
This will help you find out whats in your gun.

[OldVet]

I've read reports and seen pics of the supposed "Glock bulge." I pick up range cases as often as possible, including calibers for which I don't have (never know when I might get it). Much of the .40 cases have been fired in Glocks (distinctive primer hit and my son shoots it) and I've yet to see anything remotely resembling the pics posted on the internet. I don't find the .40 cases to be expanded any more than any other caliber fired in any other make of gun.

If the economy ever allows me to have "desposible income" again, I intend to not only to own a .40 but to reload for it too.

[kpw]

After shooting tens of thousands of factory .40 ammo through a number of different Glocks going back to 1991, without issue, I'd think they were mostly ammo problems. Either bad reloads or bullet setback that was probably the cause for the majority of issues. My original G22 had well over 20k factory and some reloads through it without bulged cases or off center primer strikes. Maybe I just got a good one...6 times in a row.

[jwhite75]

I just got my Glock 27 in 40 caliber. I have seen a few references to the 40 caliber Glock barrel not fully supporting the case and having a tendancy to go KaBoom if its a Reload/+P/Other cause.

There is even mention of it on the Buffalo Bore web site for their 40 Cal +P.


So the question is, is this something that I need to be concerned with since my Glock is new? It's not a Gen 4 because they are not making the 27 in Gen 4 yet.

Is this an internet legend or is there something to this? Can I shoot +P ammo out of my Glock or not?

As a side note, actually the 27 is in gen 4 now, my dealer has them....

[LanceORYGUN]

So the question is, is this something that I need to be concerned with since my Glock is new? It's not a Gen 4 because they are not making the 27 in Gen 4 yet.

Is this an internet legend or is there something to this? Can I shoot +P ammo out of my Glock or not?

Well, how well is the chamber supported in your Glock 27's barrel? Can you take a photo of it, and post it?

Here is a photo of some .40 S&W pistol barrels that are not fully supported. You can see that some of the side of the case is exposed in both of these barrels.






In contrast, the chambers of my S&W M&P 40 pistols and also my Walther PPS .40 are all fully supported. The sidewall of the .40 S&W case is completely covered in the barrels of my handguns.

Here is a photo that I took of the barrel from my PPS in .40 S&W:






And here is a photo of one my M&P 40 barrels. Again, you can see that the side of the case is completely covered up:





How does the barrel of your Glock 27 compare to these??

.

[Ragin Cajun]

Here is a comparason between a factory Glock 23 barrel and a replacement Lone Wolf, same size. If you observe your spent cases closely you will notice that the section of the case that hold powder and actaully expands is in the chamber and not where the feed ramp is and unsupported. The section of the case that looks unsupported is actully solid (except for the primer hole).

We will never know all the circumstances behind every kaboom but I'm sure there are a lot of details being left out. One good example for a potential problem is everytime you resize the brass, you are weaking that case. It is just like any other metal, you keep bending it and it will weaken and break.



Uploaded with ImageShack.us

[LanceORYGUN]

One good example for a potential problem is everytime you resize the brass, you are weaking that case. It is just like any other metal, you keep bending it and it will weaken and break.

I believe that is the very reason why so many gun makers advise against folks using reloaded ammunition.


.45 Glocks have even worse support in their barrels, as you can see here:




.

[MattInFla]

First off, as other posters have noted, there is no .40 S&W +P specification. Anyone manufacturing +P ammo in .40 is doing so using a specification they have invented in house.

Personally, I'd be very leery of such ammo.

Matt