How and why Guns explode.

[Mark1]

Originally Posted by mrerick

The 50 cal. ammunition was a very old and now obsolete military round. He explains in the video that it was very likely over charged. There were no obstructions in the barrel of the gun, and it fed normally prior to the catastrophic failure.

In the USA, we have a standards organization called SAAMI which publishes specifications for ammunition and firearm chambers. This includes testing of commercial ammunition to pressure standards. When a manufacturer makes a new firearm, one of the last things done prior to shipment is to "proof" the firearm using an overpressure round. This is done commercially in the United States.

In Europe, there is a similar organization called CIP. They publish similar standards for ammunition and firearms. In Europe, the majority of proof testing of firearms is done by governments. This is why Lugers have the various proof marks from government proof houses, and firearms made for export may have proof marks done by the manufacturer.

SAAMI and CIP coordinate their work.

In Europe, ammunition is also marked by proof houses, as approved through a relationship with CIP Type Approval.

Note that when our WW-I and WW-II era firearms were made, these standards organizations didn't exist, and much of the proof standards were established by manufacturers and government agencies in each individual nation working together. The same goes for the ammunition of that era. And don't forget that much of the ammunition made prior to the 1940's (and 1980's in the Eastern Block nations) used corrosive primers.

Each of the standards organizations publishes standards as free to download PDF documents.

https://bobp.cip-bobp.org/en/tdcc_public


https://saami.org/technical-informat...ami-standards/


The CIP site has a great group of videos on the procedures involved in firearm proofing.

If you ever decide to become a reloader, you need to become familiar with these dimensional and pressure standards. Note that too much powder charge in a cartridge is not the only potential cause of overpressure. This can happen easily with under charged cartridges because the bullet can have difficulty smoothly entering the leade of the barrel and engaging it's bullet's ogive in the barrel's rifling. In fact, most cartridges have multiple pressure peaks as the are discharged, travel into and through the barrel.

This isn't mentioned as a potential cause of the catastrophic failure you witnessed, but it's a distinct possibility for aging ammunition that has sustained internal damage to the powder charge. Since he was using aged military factory rounds, and he didn't know the storage conditions over the years it was stored, I suspect that this may also have been the cause of the failure.

mrerick, Good observations and sound advice in your post.
I do think it's important to note the differences between the purpose of the two organisations, the CIP and the SAAMI.
The CIP began in 1914 as the standardisation of the old European proof houses, some of which date back to the 17th century. It now regulates a common set of standards and tests which are mandatory for all guns and samples of all batches of ammunition, before they can be sold in the 14 member countries. Firearms and ammunition which have passed test must be so marked, for the benefit of the consumer.
The SAAMI is a post WW2 industry group that has developed a set of standards for the firearms industry. While these standards may be technically comparable to the CIP, they are not mandatory. A gun or ammo maker can chose to follow the SAAMI standards, or not. Manufacturers are not obliged to inform consumers if their product complies with the SAAMI standard by way of markings or any other method.
I agree that in this case, the ammo would be the obvious culprit. But we have no way of knowing how the rifle was proof tested.
Mark