The older the ammunition the less predictable. Where the ammunition was stored and the conditions it was made is something you don’t know unless you have owned it since the day it was made.
Priorities for things made in wartime are different than things made in peacetime. The bigger the war the less concern there is for “the long term”. From what little I have found in literature, the number one priority in WW2 was “getting the stuff out the door”. There was no expectation about 20 year, 45 year shelf usage. The country was either going to win this war, or we were going to be a German or Japanese speaking people. So much war material was sunk by U-Boats, destroyed in combat, before use, that putting time and effort into making something perfect did not make a lot of sense.
As an example, take a look at the last ditch weapons of the Germans and Japanese.
Also, take a look at the workmanship of WW2 Garands and the nice surface finishes of the post war Garands.
So combined with age and the haste of manufacture, WW2 ammunition is far from predictable.
I purchased several thousand rounds of WW2 ammunition back in the 80’s. I did not know about ammunition aging, but I found lots of cases which corrosion had eaten its way through the case. I fired the cases without pinhole corrosion. Later I examined all of those fired cases with a flashlight.A lot of them were internally corroded and I tossed those out. In fact, in time I tossed all of my WW2 30-06 cases. At the time, it all went bang, I don’t recall any pressure problems, but, I was lucky. Old ammunition that shows obvious signs of deterioration should have every bullet pulled and the powder dumped. Then examine the cases for corrosion.
When I learned of the mechanisms of powder aging, it is a reduction-oxidation of the double bonds in nitrocellulose, I talked to friends about the risks of old ammunition. One bud, who is a machine gunner, told me that what I told him explained the two “top cover” blowups he had had with 1950’s Yugo 8mm in his machine guns. Machine gunners shoot a lot more ammunition than rifle shooters and they want the cheapest ammunition. I bet if I knew more machine gunners I would hear more surplus ammunition blowups.
Blowup stores are rare, people try to make sense of the events and they assign reasons that are based on conventional wisdom. If they have not been taught that old ammunition can cause pressure issues, they won’t be looking for that as an answer. I found this true of slamfires. For decades people were taught the only causes for slamfires were high primers and worn out Garand/M1a receiver bridges. Primer sensitivity, the primary non mechanical cause of slamfires, did not exist. So when you look at posts about slamfires, the root cause is almost 100% believed to be high primers, even when the shooter is using factory ammunition.
Anyway I have a few posts that I am of the opinion that the blowups were due to old ammunition. I am having to break this up into several posts due to the six picture limitation on this site.
Garand Blowup with WWII ball
Garand Blowup with old US ammunition.
I have an old shooting buddy who some years ago was shooting some WWII ball (don’t know whose) but his M-1 was disassembled in a rather rapid fashion. He was lucky only his pride was hurt. He said he took a round apart and found rust looking dust along with the powder. Bad powder. Just sayin…..The op rod can be rebuilt which might be a good way to go. Op Rods are getting harder to find and when you find one a premium price is required so it seems. Garands require grease. I’m not sure if you are aware of this. If you are, please no offence taken.
There was a thread on another forum titeled “What’s in your ammo can” and
many guys had old surpluss ammo so I told this story. Ty (arizonaguide) asked that I come put it here also so here it is boys, draw your own conclutions.
Back in the mid 80s my Dad and a bunch of us went shooting in Arizona. Dad had a couple thousand rounds of WWII surplus .30M1 (30-06) ammo that looked great on the outside cut his M1 in half in his hands. He was kneeling with elbow on knee when the first round of this ammo went BOOM! We were all pelted with sand and M1 shrapnel.
When the dust cleared Dad was rolling around on his back with buttstock in one hand, for stock in the other, barrel and receiver hanging by the sling around his arm trying to yell “mortar” thinking he was back on Okinawa in battle. The blast had removed his ear muffs, hat, glasses, and broke the headlight in my truck 15 feet away but Dad was only shook up and scratched a bit once he got his wits back. It sheared off the bolt lugs, blew open the receiver front ring, pushed all the guts out the bottom of the magazine, and turned the middle of the stock to splinters.
After a couple hours of picking up M1 shrapnel we headed to the loading bench and started pulling bullets. Some of the powder was fine, some was stuck together in clumps, and some had to be dug out with a stick. It didn’t smell and was not dusty like powder usuley is when it’s gone bad. Put it in a pie tin and light it and it seemed a tad fast but not so you would think it could do that, wasent like lighting a pistol powder even. He had 2000 rounds of this stuff and nun of us were in any mood to play with it much after what we watched so it all went onto a very entertaining desert bon fire. I got the M1 splinters when Dad died last year and will post pix here below for your parousal and entertainment.
Anyway, I no longer play with any ammo I am not 100% sure has always been stored properly . . . cheap shooting ain’t worth the risk to me anymore! I still buy surpluss if the price in right but I unload and reload it with powder I am sure of or just use the brass.
She was a good shooting servasable Winchester M1 before this.