what happens if you overload ammo?


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gofastman
September 1, 2011, 08:32 PM
sounds like a silly question, but what exactly happens?
say you load 11grs of longshot behind a 180gr slug (max is 9.5grs)
does the gun blow up in your hand or does the brass act like a fusible link and blow out?

the gun in question is a glock 20

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sugarmaker
September 1, 2011, 08:53 PM
Depends on the gun. Missing eyes and fingers are rare but not unheard of. Often it just ruins the gun w/o hurting the shooter.

sniper5
September 1, 2011, 08:55 PM
At the least you will experience premature wear on barrel, chamber, slide, recoil springs, frame, etc.

Or at any time you could experience a catastrophic failure. Just google whatever make of firearm you have and add the word kaboom and start looking at the pictures. In your case it was Glock so these were the first 4 I found out of several pages (oops, my bad they slipped in some XD's, but I think you get the idea):

SlamFire1
September 1, 2011, 08:55 PM
A Glock owner posted these pictures of what happened when the case head of a factory AMERC round ruptured.


http://img.photobucket.com/albums/v479/SlamFire/Blowups/GlockKBglock351.jpg

http://img.photobucket.com/albums/v479/SlamFire/Blowups/GlockKBAmerAmmunition1.jpg

http://img.photobucket.com/albums/v479/SlamFire/Blowups/GlockKBgz-m30kb61.jpg

http://img.photobucket.com/albums/v479/SlamFire/Blowups/GlockKBm20-crack1.jpg

There are lots of Glock blowup pictures on the web. What happens is an individual event, highly variable.

gofastman
September 1, 2011, 09:06 PM
I guess Im asking why this would happen:
http://www.thegunzone.com/glock/images/22kb.jpg


compared to the brass blowing out:

jmorris
September 1, 2011, 09:16 PM
By how much? A double will result in the photos above in some cases. Others can result in cases not being extracted. A flat primer would be the result of one that is just a tad overloaded.

rfwobbly
September 1, 2011, 09:38 PM
I guess I'm asking why this would happen:

Too much chamber pressure. Probably due to a double charge of powder.

wvshooter
September 1, 2011, 09:47 PM
I guess Im asking why this would happen:


Are you asking why a barrel would split open? Wouldn't the answer be simple physics.

Modern smokeless powders are very powerful, especially when compared to the old black powder. Guns are designed to operate within certain pressure limits. Exceed the limits and you're in the danger zone. Even if you stay within the allowable powder charges but accidentally seat a bullet too deep pressures can go up real fast.

Can't imagine anyone taking a chance on having a gun blow up in their hand or anywhere near them for that matter. Any part of the gun can become a projectile. Could result in loss of fingers or eyes or nose or some other very nasty injury. Imagine an ejector being lodged three inches deep in your forehead.

gofastman
September 1, 2011, 09:56 PM
Are you asking why a barrel would split open?
yeah, as opposed to the brass blowing out

rcmodel
September 1, 2011, 10:06 PM
what happens if you overload ammo?A Series of Unfortunate Events, leading to Very Bad Things!

rc

kingmt
September 1, 2011, 10:21 PM
If the barrel split I doubt you find the brass. If you did it would be trashed also.

rfwobbly
September 1, 2011, 10:29 PM
yeah, as opposed to the brass blowing out

Well, that has to do with the pressure. The gun is like a garden hose. Just a little too much water pressure and the hose starts to leak around the couplings. 50 psi too much pressure and you might get a pin hole leak. (Brass blowing out.) 200 psi too much pressure and the hose might split open. (Barrel bursting.)

trex1310
September 1, 2011, 10:40 PM
I witnessed a gentleman fire an XP-100 and the bolt exited the gun
and ruptured the radiator of a pickup truck that was parked some
30 feet behind the shooter (who was in the Creedmoor position).
The shooter had loaded Bullseye when he should have loaded Blue Dot.
He was lucky that he or someone else wasn't killed.

billybob44
September 1, 2011, 11:56 PM
sounds like a silly question, but what exactly happens?
say you load 11grs of longshot behind a 180gr slug (max is 9.5grs)
does the gun blow up in your hand or does the brass act like a fusible link and blow out?

the gun in question is a glock 20
I REALLY hope that this thread has nothing to do with the LW barrel that you have for sale???

beatledog7
September 2, 2011, 12:14 AM
What happens if you overload ammo? Nothing, unless you're unwise (I'd say "stupid" but the moderators might not like it) enough to fire it. If you know it's overloaded, pull the bullets and start over.

Furncliff
September 2, 2011, 12:19 AM
http://smith-wessonforum.com/attachments/s-w-revolvers-1980-present/7937d1258391561-s-w-kaboom-626-image004.jpg

RandyP
September 2, 2011, 12:26 AM
Stuff blows up in an unpredicatble manner sometimes, using over-max loads is not an option for ME. I agree that calling someone who did use over-max charges stupid might be an insult to stupid people.

pdosh
September 2, 2011, 12:26 AM
I had an overload in a SIG. I don't know how much but it blew the back end of the brass off, and the extractor and spring. The mag was also blown out. No injury, thankfully. That was it for the day and after spending about 50 bucks I was back in business. The barrel or frame wasn't hurt. But it's not a polymer framed gun. I had just started using a progressive loader when it happened. I've since added a RCBS Lock Out die. Not cheap but I'm worth it!

Lost Sheep
September 2, 2011, 12:39 AM
I think I understand the question:

Will brass usually fail before steel? Brass is a softer, weaker metal. You would think so. If so, would the brass fail, releasing the overpressure before the steel of the gun sends steel shrapnel flying about.

The answer is "no".

The full answer lies in the science of internal ballistics.

Manufacturers of semi-auto guns seem to have built their guns so that if the brass does let go, or the steel of the barrel or slide fails, the exhausting gasses are directed in (relatively) safer directions than back at the shooter, but the safety added thereby is minimal at best. Witness the photographs you have seen and the testimonials.

There has been no way discovered yet to protect a shooter from overpressures.

Unlike a boiler or pressure cooker, there is no reliable safety release valve for firearms that will "let go" before catastrophic failure occurs. Sometimes you get a "kaboom" and sometimes you get a "phffft".

I suspect it has more to do with transient pressure waves and things going wild far too fast for brass or steel to react in an orderly fashion.

It would be interesting to see if a laboratory pressure barrel in 45 Colt could be fitted with a release mechanism to relieve pressure at say, 20,000 psi and then load up some SAAMI spec loads and some of Dick Casull's overloads.

I would be surprised if it hasn't been tried, but I doubt if it has ever worked, at least not in a firearm small enough to be portable and powerful enough to be useful.

Thanks for an interesting question.

Lost Sheep

Rail Driver
September 2, 2011, 12:46 AM
Here are a couple other examples:

http://cdn5.thefirearmsblog.com/blog/wp-content/uploads/2009/11/6920boltcarriersplitf-tfb.jpg

and here is a link to a forum post/thread regarding ammunition overcharges:

http://smith-wessonforum.com/reloading/112638-glock-blows-up-3.html#post1204237

http://smith-wessonforum.com/attachments/reloading/9110d1260295447-glock-blows-up-kaboom6.jpg

Walkalong
September 2, 2011, 08:46 AM
A Series of Unfortunate Events, leading to Very Bad Things!
Yep.

The brass case seals the chamber, which is the only part of the gun able to handle the pressures generated by the cartridge when fired.

If it ruptures from over pressure, the HOT, HIGH PRESSURE, HIGH VELOCITY gases wreak havoc on the firearm.

SlamFire1
September 2, 2011, 12:22 PM
I know people keep saying pressures but it really translates to load.

Guns are designed to carry a load.

So what is the load, well it is pressure times a surface area.

Obviously you increase the pressure for the same surface area, the load goes up.

However, when you blow the case head and gas escapes into the mechanism, the surface area goes up.

Assuming the pressure stays the same (and it does not) you can imagine that doubling, tripling the surface area the gas has to push against, the load goes way, way up.


I have had bicycle tires that operate at 125 psia, does not seem like much.

But you put that 125 pounds per square inch across the side of a house, (say 60 foot by 12 foot rectangular surface) and the wall completely disappears.

Says here, that 10 psia overpressure will blow your arms off.

http://en.wikipedia.org/wiki/Overpressure

Stay away from Thermonuclear bombs.

Four (4) miles away from the epicenter the blast of 1 MT Bomb, overpressure is 6 pounds per square inch. Winds are 180 miles per hour. All standard houses and buildings "implode" with that overpressure and then are swept clean with the blast winds. (2) Pounds per square inch crush a house.


http://www.parowanprophet.com/Nuclear_War_Comes/May_25_83_Revelation.htm

highlander 5
September 2, 2011, 12:38 PM
Had a buddy hat constantly over loaded his 357 Maximum in a Contender. he was lucky in all that happened is he was have case head seperations.

gofastman
September 2, 2011, 07:44 PM
think I understand the question:

Will brass usually fail before steel? Brass is a softer, weaker metal. You would think so. If so, would the brass fail, releasing the overpressure before the steel of the gun sends steel shrapnel flying about.

The answer is "no".
thank you, that answer is clear as a crystal, thanks!

Walkalong
September 2, 2011, 08:48 PM
If so, would the brass fail, releasing the overpressure before the steel of the gun sends steel shrapnel flying about.

The answer is "no".
The answer is yes, the brass case head will fail before the chamber does, although in a dramatic overload, it can come pretty much simultaneously.

Lost Sheep
September 2, 2011, 10:17 PM
Walkalong, 64 minutes after gofastman thanks me for a clear answer, you come along and blow it apart! I had to laugh.

The point of most of my post is that there is no clear, definitive anwer, which you proved. :)

(Actually, the "no" is pointed more towards the part of the question that refers to the brass releasing pressure and implicitly protecting the rest of the gun and/or the shooter and bystanders.)

When failure occurs among many components simultaneously, it pretty much doesn't matter which fails first. The steel supports the brass head. If the steel fails, the brass surely will. If the brass fails, the steel might or might not, but even if it does not, the results are almost always unpleasant.

Internal ballistics. A lifetime's worth of study.

Lost Sheep.

Walkalong
September 3, 2011, 10:37 PM
Which came first, the chicken or the egg? :D

ljnowell
September 3, 2011, 10:58 PM
Which came first, the chicken or the egg
Doesnt matter, the colonel is gonna fry it either way. Same with the chamber and the case.

1SOW
September 3, 2011, 11:21 PM
If you have just enough pressure to blow the brass, then just the brass will blow. If you have enough pressure to rupture the steel, then the brass will blow, but so will the steel.
Somewhere between these two pressures other bad things can happen, like the pics of cracks or large "bulges" in the barrel; but yes, the brass may relieve "some" of the pressure. Some of the pressure will be relieved "bypassing" the bullet.
There are some high-speed pics on the forum of a pistol being fired and showing the gasses exiting the barrel before the bullet. "Some" of the pressure was releved.

Walkalong
September 4, 2011, 09:43 AM
Doesnt matter, the colonel is gonna fry it either way. Same with the chamber and the case... :D

Carl N. Brown
September 4, 2011, 10:08 AM
I have never heard of brass cartridges being designed to vent pressure from the barrel; I have always heard they were designed to expand, seal and contain the pressure. Take the case of a ThompsonCenter singleshot pistol, in which the casehead is completely enclosed by the barrel and breech face: even though brass is softer than steel, there is no way for the brass to give and vent overpressure that would burst the barrel. If overpressure gets vented at all, it is usually where the primer blows out and the excess pressure vents through the firingpin hole in the breech (and the barrel may bulge or burst anyway).

Also, with a lot of smokeless pistol powder that 11.5gr over a 9 gr max is a 28% overcharge by powder weight, but the increase in pressure can be exponentially greater than 28%: the increase in pressure as the charge weight increases is not a straight line, but is an upward curve. Which is why I visually inspect cases for double charges before seating bullets.

evan price
September 5, 2011, 07:59 AM
Consider a cartridge in a firearm that is in battery, breech closed. The brass itself is supported in every dimension externally by steel and has almost nothing except the rim edge exposed. IN order for the brass to fail at all there would have to be some place for the expanding brass to go. Since the brass is surrounded nearly completely by steel, the only way for the brass to expand is either forward towards the barrel (which is restricted by the bullet, even if it is moving) which causes case head separations, or else the steel blows apart. That is why case head separations are so dangerous. They are a tiny bit away from a kaboom.

Think of the brass case as a gasket instead of a mechanical part.

cfullgraf
September 5, 2011, 09:47 AM
Another piece to the issue not often addressed is the rate of rise of the pressure.

An over charge of fast burning powder may reach a lower pressure than one of slower burning but the more rapid rise of the pressure in the fast burning powder may cause more damage/destruction.

Kind of like hitting something with hammer versus pushing on it with a hydraulic press.

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