Decaying gun powder question

The way I see it, when gun powder takes in moisure and becomes wet, then slowly coalesces into clumps, which then agglomerate into a big blob and then gun powder stops moving when shaken, and later it eats through cartridge wall. One can hear this because the sound of gun powder movement becomes less and less.
What happens if one fires a round which is half the way through this process, i.e. when you still can hear the powder movement but it is greatly diminished? Will it fire?

Most of the cartridges with deteriorating smokeless propellant ( ‘gun powder’ is a synonym for ‘black powder’ and should not be used when smokeless is meant) on this forum are German-made 7.9 m/m rounds made from the late 1930s to the end of WW.2. Most of these German loadings are typically a case-full load and make no sound when shaken. I am not certain on this final point but am fairly certain the propellant is breaking down because of acidic materials used in its manufacture which were not fully purged in the final stages of manufacture; i.e., moisture not the major factor.

Why corners were cut in making the powder I don’t know, but suspect it was thought the powder would be stable long enough for its makers that its eventual deterioration was of little concern. The Third Reich wasn’t thinking much of cartridge collectors in 1938. Jack

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I am pulling powder fron US made WWI era 7.62x54R’s, about half of them have sound, sometimes greatly diminished, so I am wondering if they are shootable.

Most powders from this era were not washed enough as Jack notes. The same problem exists with .30-40 & 30-06 military loadings.

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It can also be very hard to know how badly the acid has corroded the brass. I had a 9.5x66 Vom Hofe Super Express that looked perfect on the outside. When I started waxing the cartridge, the neck snapped off cleanly at the shoulder with very little force. The inside was heavily corroded green. The powder was not appreciably clumped but looked more or less as expected (other than containing some green copper corrosion particles). So my conclusion would be that any round from that era might be at least suspect.

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Evening All,
This is a photo of the propellant from a .303 Mk VI Ball round I pulled yesterday!

Prop From 303 MkVI|690x517

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Neat, I have not seen the same problem with cordite yet. I am re-posting your photo from above for easier viewing.

A couple of photographs of (inerted) BP 577-450’s.

Thanks Sksvlad, I’m not sure what I did to get just the link and not the picture in my post.

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