Accurate Arms warning about .40 S&W

[ochmude]

I was just on the Accurate Arms website looking for load data, and I came across this warning.

WARNING!!!

In recent years it has become very apparent that there exists a situation regarding some pistols chambered for the 40 S&W cartridge. Some of the pistols currently available to shooters may not provide complete support to the case when a cartridge is chambered.

The Sporting Arms and Ammunition Manufacturers Institute (SAAMI) has established a maximum average pressure for the 40 S&W of 35,000 psi. The loading data published by Accurate Arms was developed in our ballistic laboratory in accordance with SAAMI test methods and equipment and does not exceed this figure. This information is safe for use in firearms which provide complete support of the case. Failure to fully support the case with cartridges of such intensity may result in bulged cases, ruptured cases, separated case heads or other consequences which may result in damage to the firearm and/or injury or death to the shooter and/or bystanders. This can happen no matter whose propellant is used.

If you own a firearm chambered for the 40 S&W, we recommend you contact the manufacturer to determine if the case is fully supported, or have a competent gunsmith examine the firearm and determine the amount of support provided the case. If your firearm does not provide complete support for the case, DO NOT USE Accurate Arms Company data or products to reload your 40 S&W ammunition.

This is the first time Accurate Arms Company has felt it necessary to place such a restriction on the use of our products, but the continued safety and welfare of the shooting public compels us to do so.

source

Are they talking about Glocks that don't have fully supported chambers? It just surprised me as this is the first time I've read an official warning from a factory about the .40 and Glocks, or other such firearms with unsupported chambers.

 

[terraformer]

I wonder what difference the ma**h*** makes. It is at a very strong spot on the case and highly localized. But still, where is the support issues in the glock? Along the bottom up further towards the bullet?

 

[Gammon]

The problem is the unsupported area where the chamber is throated to allow the round to enter. Very few stock guns have "fully supported chambers" as this throating leaves a portion of the base of the case unsupported. Some barrels are worse than others with Glock among the worst. There are no real safety problems with new ammo, but repeated loadings of high pressure rounds could weaken the brass. The common problem is the bulge created by brass flow into the unsupported area of the chamber. This bulge can become a 'belt" when the case is resized which can interfere with chambering. This can be avoided by using an "undersized" resizing die. Damage or weakening of the brass can be avoided by keeping the pressure down; stick with 165pf loads or less. If you must "push the edge of the envelope" (which I do NOT recommend) use only new brass or used brass in excellent condition; it's your face!

 

[Scrivener]

The problem is the unsupported area where the chamber is throated to allow the round to enter. Very few stock guns have "fully supported chambers" as this throating leaves a portion of the base of the case unsupported. Some barrels are worse than others with Glock among the worst. ... This can be avoided by using an "undersized" resizing die. Damage or weakening of the brass can be avoided by keeping the pressure down; stick with 165pf loads or less. If you must "push the edge of the envelope" (which I do NOT recommend) use only new brass or used brass in excellent condition; it's your face!

This can best be avoided by using a barrel that actually supports the entire cartridge, instead of exposing a significant section because of a manufacturing short-cut.

 

[Rob Boudrie]

A closely related issue is that most handguns will fire when slightly out of battery. While there is a mechanism to prevent this, there is generally a very small amount of "out of a batteryness" that is tolerated by the disconnector - otherwise, the tolerances would be so tight as to impair reliability. If you doubt this, pull your slide ever so slightly back while your unloaded gun is cocked and pull the trigger - you'll find there is indeed a small amount of "out of battery" tolerated.

Now, consider what happens when you are shooting reloads with pregnant guppy syndrome and one sticks out just far enough to prevent the chamber from going fully into battery, but it's far enough to let the disconnector disconnect. Add to that a construction from non-tradtional (ie, not blued steel) materials that are fare more likely to suffer catastrophic failure when a case head ruptures than an old school gun like a steel frame 1911, and a case that is already weakened from previous use, and you've got the ingredients of a kaboom.

Case head ruptures have happened with semi-autos for years, but are not as noticeable, or as widely reported on the net, when the reaction is "Oops, case head rupture - inspect gun, reassemble or replace magazine, go back to shooting" rather than "look into getting plastic frame replaced".

ps: If you want to really increase the chances of a 40 S&W case head blowout, load with Clays.

 

[TonyT]

Hodgdon has had a similar warning in their reloading manuals for several years. Hodgdon will also not provide any reloading data for their powders using lead bullets in 40 S&W.

 

[drgrant]

This is their daft way of dealing with the AA#5 Glock KB problem. It's easier to just not use AA#5 and move on with one's life. (It's linked anecdotally to a crapload of Glock KB's). Usually whenever there is a reloading based KB with a Glock, a majority of the time AA #5 is somehow involved. This sticks out to me because among reloaders AA handgun powders are only mildly popular to begin with, so the correlation to me is somewhat telling.

-Mike

 

[Scrivener]

Hodgdon has had a similar warning in their reloading manuals for several years. Hodgdon will also not provide any reloading data for their powders using lead bullets in 40 S&W.

Thus inflicting a Glock/H&K limitation on the rest of us.

For that matter, I used 175 grain LSWC in a G23 for some time without any issues. Then again, I also used the cleaning brush and wasn't an idiot about letting lead accumulate in the bore.

 

[Lucas McCain]

As has been posted on this forum by people wiser than I "No good can come of the .40"

 

[Scrivener]

As has been posted on this forum by people wiser than I "No good can come of the .40"

Since we're now using the quotes of others, here's my submission:

A man has to know his limitations.

 

[RKG]

A closely related issue is that most handguns will fire when slightly out of battery. While there is a mechanism to prevent this, there is generally a very small amount of "out of a batteryness" that is tolerated by the disconnector - otherwise, the tolerances would be so tight as to impair reliability. If you doubt this, pull your slide ever so slightly back while your unloaded gun is cocked and pull the trigger - you'll find there is indeed a small amount of "out of battery" tolerated. . . .

Interesting issue. If you define "out of battery" to mean that the slide-and-locked-barrel combination is not absolutely fully forward, you are correct. However, long before the disconnector has lifted (thus re-enabling the trigger to reset and then refire), the barrel will be locked to the slide and the breach face will be as tight against the case head as it it ever will be.

Thus, in the test suggested in the quote, while it is true that the pistol may fire with the barrel-and-slide combination ever so slightly aft of full forward travel, nonetheless the breach is still fully locked and the case is as fully supported as it would be if the slide-and-barrel combination were fully forward.

Locked breach autos provide a distance (generally 1/4 to 3/8") where the locked slide-and-barrel combination can travel aft before the barrel begins to unlock. Thus, as you begin to move the slide aft on your pistol, you will see that the slide and the barrel move together for that distance, and only after they have moved back that distance does the barrel stop moving and the slide continue aft on its own. Part of the reason for this is to allow chamber pressure to decay to the point where unlocking is safe. Another part of the reason is precisely to insure re-locking long before the disconnector can rise.

If, therefore, we defined "out of battery" to mean "prior to the time that the breach locking mechanism has fully locked," I would disagree with the first sentence of the quotation.

Respectfully, I would also question the relevance of even this theoretical observation. In practice, the typical locked breach auto pistol cycles so quickly that the slide and barrel are fully in battery long before the shooter can allow the trigger to reset, and the disconnector cannot fully rise until the trigger has moved forward.

 

[terraformer]

Since we're now using the quotes of others, here's my submission:

You catch more flies with honey than with vinegar.

 

[Gammon]

This can best be avoided by using a barrel that actually supports the entire cartridge, instead of exposing a significant section because of a manufacturing short-cut.

Glock barrels are not the result of "manufacturing short cuts". They are built to military specs for maximum reliability. Military weapons are not designed to produce brass suitable for reloading, so the abused brass is not a concerned. As I mentioned before, just keep the pressure down and the stock barrel will work just fine.

 

[CRSIII]

Where's Jim?

 

[Gammon]

A closely related issue is that most handguns will fire when slightly out of battery. While there is a mechanism to prevent this, there is generally a very small amount of "out of a batteryness" that is tolerated by the disconnector - otherwise, the tolerances would be so tight as to impair reliability. If you doubt this, pull your slide ever so slightly back while your unloaded gun is cocked and pull the trigger - you'll find there is indeed a small amount of "out of battery" tolerated.

Now, consider what happens when you are shooting reloads with pregnant guppy syndrome and one sticks out just far enough to prevent the chamber from going fully into battery, but it's far enough to let the disconnector disconnect. Add to that a construction from non-tradtional (ie, not blued steel) materials that are fare more likely to suffer catastrophic failure when a case head ruptures than an old school gun like a steel frame 1911, and a case that is already weakened from previous use, and you've got the ingredients of a kaboom.

Case head ruptures have happened with semi-autos for years, but are not as noticeable, or as widely reported on the net, when the reaction is "Oops, case head rupture - inspect gun, reassemble or replace magazine, go back to shooting" rather than "look into getting plastic frame replaced".

ps: If you want to really increase the chances of a 40 S&W case head blowout, load with Clays.

This problem is aggravated by striker fired pistols. The striker spring is actually trying to prevent the slide from going into battery.
PS I don't have any use for Clays either.

 

[Gammon]

Hodgdon has had a similar warning in their reloading manuals for several years. Hodgdon will also not provide any reloading data for their powders using lead bullets in 40 S&W.

No big deal. As long as you are loading hard cast bullets, you can use the jacketed data for the same weight. Just start low and stay below 1000 fps.

 

[WILDCATT]

have you seen the blown guns pictures on other sites very impresive.most that shoot glocks buy after market barrels.I dont have glocks and I would not have a 40 cal with 35,000 lb chamber pressure when the 1911 will do all I ask of it.

 

[Stef]

This can best be avoided by using a barrel that actually supports the entire cartridge, instead of exposing a significant section because of a manufacturing short-cut.

Are those barrels machined from pure unobtanium? If you're looking for a barrel that supports the entire cartridge, you're not going to find it in ANY pistol based on John Browning's tilting barrel design.

 

[EddieCoyle]

Interesting issue. If you define "out of battery" to mean that the slide-and-locked-barrel combination is not absolutely fully forward, you are correct. However, long before the disconnector has lifted (thus re-enabling the trigger to reset and then refire), the barrel will be locked to the slide and the breach face will be as tight against the case head as it it ever will be.

Also, if the barrel is not locked to the slide (out of battery with the chamber end of the barrel slightly tilted down), won't the firing pin miss the primer?

You catch more flies with honey than with vinegar.

I don't think he's familiar with that one.

 

[drgrant]

Are those barrels machined from pure unobtanium? If you're looking for a barrel that supports the entire cartridge, you're not going to find it in ANY pistol based on John Browning's tilting barrel design.

Maybe that's Scriv's way of telling us to buy a revolver?

-Mike

 

[Rob Boudrie]

Also, if the barrel is not locked to the slide (out of battery with the chamber end of the barrel slightly tilted down), won't the firing pin miss the primer?

If it's out that far it will, I'm talkimg microsmidgens .

 

[Stef]

Maybe that's Scriv's way of telling us to buy a revolver?

Heh, could be.

 

[Jose]

Very fast burn rate powders + high pressure handgun cartridges + overworked brass + lack of case support = exploded pistol

 

[Mark from MA]

Are those barrels machined from pure unobtanium? If you're looking for a barrel that supports the entire cartridge, you're not going to find it in ANY pistol based on John Browning's tilting barrel design.

Kinda my thought. I think it's got more to do with the chamber tolerance than anything to do with support. Guns made to function reilably every time have loose chambers, and they are not thinking about reloads or match grade accuracy. They are thinking about reliability when the gun is loaded with sand, crap and without cleaning forever.

That and the 40 cal is a high pressure round and powder and relloading manufacturers are playing cover your ass....

If the chamber support area is so different on say a lone wolf barrel...why would I be able to drop it in without any fitting? This is what leads me to believe the whole thing is about chamber tolerance.

 

[WILDCATT]

glocks

the blown guns I saw had very thin walls where they blew and the ramp is large so theres little support. for the base of the shell.

 

[Scrivener]

Glock barrels are not the result of "manufacturing short cuts". They are built to military specs for maximum reliability. Military weapons are not designed to produce brass suitable for reloading, so the abused brass is not a concerned.

Glock built its .40's on 9mm frames. How is that NOT a "manufacturing short cut?"

As I mentioned before, just keep the pressure down and the stock barrel will work just fine.

A man's got to know his limitations.........

 

[Scrivener]

Are those barrels machined from pure unobtanium? If you're looking for a barrel that supports the entire cartridge, you're not going to find it in ANY pistol based on John Browning's tilting barrel design.

I should have been more precise. No; the 1911 does not support the ENTIRE cartridge. It does expose the extractor groove and head of the case - the thickest part of the case.

However, UNLIKE Glocks, the 1911 barrel DOES enclose and support all the case wall - the thinnest part of the case.

I had 2 of my SVI's apart this past weekend and checked, just to be sure.

 

[Gammon]

Glock built its .40's on 9mm frames. How is that NOT a "manufacturing short cut?"



A man's got to know his limitations.........

We were discussing the dimensions of Glock chambers and case support. I fail to see how this invoves the reciever.

 

[Scrivener]

We were discussing the dimensions of Glock chambers and case support. I fail to see how this invoves the reciever.

I believe the technical term is "cause and effect."

 

[DukeInFlorida]

I'm pretty sure that was one of the design criteria, and NOT a result of some manufacturing short cut.

Glock built its .40's on 9mm frames. How is that NOT a "manufacturing short cut?"