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View Full Version : Update on Korean Surplus Ammo Blow-up



Uncle Grinch
10-22-2006, 03:17 PM
I promised to give everyone a follow up if I found anything strange when I broke down my Korean suplus 30-06 (KA-71) ammo and that is what I found.

This ammo was loaded with 49.7 grains of an extruded powder and topped with a 150 grain FMJ with an open base. There was mixed in this same lot about half a dozen rounds with ball powder.

Some of the bullet bases were very corroded and this corrosion had spread to the powder, as it had small bluish/green debris mixed in. After I kill all the primers, I'm going to cut some of these cases in half for a closer examination. I suspect this may have been the root of my case blow-up.

One of the cases containing extruded powder was hard to dump and after I managed to get it out, I found it lumped together in what looked like an oily or wet residue.

I have included photos of these for your review.

ron brooks
10-22-2006, 05:29 PM
Could at least part of the problem have been that the corrision on the bullets was causing increased bullet "pull" and this caused a large increase in preassure therefore causing the case blowups.

Ron

jhalcott
10-22-2006, 08:24 PM
Have you measured the blown case? Why would it "burn" a hole near the thickest part of the case? I'd think the case would come apart a little farther up.
but then I ain't s'posed to be thinking so much!

Frank46
10-23-2006, 03:56 AM
Mike, some years ago, a buddy gave me a bunch of 1933 vintage FN 175gr steel jacketed ammo and some 1940's dated 7mm military ammo. The 1940's era stuff all showed severe corrosion on the base of the bullet and were very hard to pull with an inertia bullet puller. The 1933 stuff pulled easily but the corrosion on the steel jacketed bullets was no way as bad as the later stuff. I had some 1912 and 1920 dated portugese kropatschek 8mm ammo and some of the cases showed severe neck splits. Bullets were so loose you could pull them out with your fingers. None of the steel jacketed nor the cupro nickle bullets showed any marked corrosion. Could be the way the stuff was stored over the years (hot damp or humid conditions) may have contributed to the corrosion. The 8mm stuff was all labeled in portugese in 10 round boxes. Must have been repacked at some point in time. Your post on the blow up I related to a new shooter. He had quite a lot of the KA '06. I mentioned the incident and that it was corrosive. He had been shooting it in a dcm garand. At a local gun show saturday one dealer had korean PS non corrosive '06. I told him that he would be better off using that. I don't think he knew the effects of shooting corrosive ammo and cleaning properly. I still have some of the black vile smelling corrosive U.S. bore cleaner. Stuff works when I have some corrosive ammo to shoot off. Frank

NickSS
10-23-2006, 05:40 AM
I have used several hundred rounds of KA 73 ammo in several guns. It is corrosive but I never had a problem with cases splitting. I have had the exact same type of head rupture on some french suplus 30-06 ammo a long time ago. The ammo was less than 15 years old at the time but the brass was brittal. I also had a Remington 30-06 case fail the same way. The ammo was old but it looked good. Of the 100 rounds of it I shot they all went off but one split the head. The rest of the brass I reloaded at least 15 times each without a single failure. I suppose some cases are just more brittal than others.

Ricochet
10-23-2006, 01:54 PM
I'll suggest that the extreme corrosion of the copper on the bullet is a sign that the powder in the case had decomposed. That releases oxides of nitrogen that are especially corrosive to copper. Decomposed smokeless powder will generally give a higher pressure on firing than powder in good condition, because the grains become brittle and shatter on firing, exposing much more surface area to the flame. The brass cases also may have been weakened by corrosion from the nitrogen oxides.

I've also seen this happen on a beautiful old Gibson guitar that had been stored for years in a closed case. The celluloid (nitrocellulose) pickguard was shrunken, cracked and crumbling, the nitrocellulose lacquer wood finish was badly alligatored, and the nickeled brass hardware was thickly encrusted with verdigris.

Bullshop Junior
10-23-2006, 11:54 PM
Are you going to keep the bullets or toss them. If you are going to toss them, I want them. If you want to keep them, pay no atentoin to the man behind the curtins.(whitch is me)
Thanks
DANIEL/BS JR.
:castmine:

Dale53
10-24-2006, 12:13 AM
You illustrate a classic case of "Case Failure". Whether it is chemically induced or just bad brass I have no idea. It does not seem to be a "Pressure Problem".

Many years ago, I had TWO similar case failures in one day. Talk about a bad day. Actually, it wasn't too bad. I was shooting a Springfield O3A3, which handled the gas really well. However, if I had not had shooting glasses on I would have probably lost my vision. My glasses were burned and brass bits were buried in my face around the glasses. Because I was wearing good glasses, it was a minor annoyance. When they went off, it was as if my head was inside a bell that someone had struck HARD with a sledge hammer.

My ammo was VERY old (1918 U.S. miltary ammo). I later researched it and learned that that particular lot and brand had a reputation for bad breass and most of it had been destroyed many years before. To make sure no one got any of the stuff I had left, I buried it in a hidden "grave".

I would dispose of all of the remaining cartridges in a manner that would not allow anyone to get hurt in the future. This represents the worse possible case failure scenario - a true "Catastrophic Case Failure". I typically ruins rifles and hurts people. I was very lucky.

FWIW
Dale53

Uncle Grinch
10-24-2006, 06:17 PM
Daniel... I have already cleaned them up with the exception of the ones with the really corroded bases and plan on using them in my Greek HXP brass...(sorry... but I would have asked too!)

Dale.. You are absolutely correct about wearing eye protection. This was my second exposure to blow back and it can do some serious damage it it were not for the right protection. Of course the rifle's ability to handle this is important too and is often overlooked now'adays.

Bullshop Junior
10-24-2006, 07:57 PM
Daniel... I have already cleaned them up with the exception of the ones with the really corroded bases and plan on using them in my Greek HXP brass...(sorry... but I would have asked too!)
That is just fine! I only asked becouse I do not like seeing perfecty good goodies going by-by!:mrgreen: I would have used them in my swiss rifle, or as dad does, load them down side up in a 30/30.:Fire:
DANIEL/BS JR.

Freightman
12-02-2006, 10:44 PM
That looks just like one I had in my Garand (no damage to me or the rifle) I pulled all the ones I had down and reloaded. I found a great big difference in charges in the same date and headstamp. They ranged from 46g to 54g of the same powder from the same date. Haven't used anymore Korean since and have went to my reloads exclusive.

snowtigger
12-04-2006, 03:13 PM
Are you going to keep the bullets or toss them. If you are going to toss them, I want them. If you want to keep them, pay no atentoin to the man behind the curtins.(whitch is me)
Thanks
DANIEL/BS JR.
:castmine:

Daniel, Someone gave me about ten pounds of cast .30 cal bullets. They are gas checked and lubed, but they are pretty dirty. I didn't have the heart to throw them in the pot. I am not going to use them, so if you want them, you are welcome to them. I have no way of testing them, bt they seem pretty hard.