Old British pathe film

Please note the spools of Cordite being fed out and cut to length.

Now that was interesting, the mix of old school automation and human interface.

I read that the cases were not necked down until after the cordite had been installed. Wish I had those machines.

Interesting if short. Last week I was at the Sierra plant in Sedalia, Mo....yet again....and took the tour....yet again...and some of the processes are still the same.

dp, I read the same thing about the cordite being loaded into the case before the case was necked. Makes sense.

I did not think mercuric primers were used with cordite.

Interesting.

I noticed they mentioned that the lead core had a metal tip before it was put into the jacket.

This, I think, makes it a Mk 7, which had an aluminium tip (inside the jacket).

At one stage in the war, there was a shortage of almost all metals and that tip was replaced with papier mache. I remember reading a book by a Sir Sidney Smith (an early pathologist) talking about it.

And that Royal mint in Pretoria became Pretoria Metal Pressings, which became PMP, which still makes ammo in RSA up untl a few years ago at least (I have no idea if they are still going, I haven't seen any info either way).

What kind of primer would have been used?

When Cordite was first introduced would it not have been impossible to have used anything but mercuric primers? Was there something else in the late 1800's I'm ignorant of? If so it was still corrosive.

Mercuric primers were not, as far as I know corrosive as such. They did attack cartridge cases and weaken them due to reaction of mercury with the brass causing an amalgam. I could be wrong, but that's what I remember.

This was a reason to replace it with potassium chlorate, which didn't attack the cases and so allowed for reloading.

The problem with potassium chlorate was it left a deposit of potassium chloride (chemically similar to sea salt - sodium chloride) in the barrel, leading to rapid rusting if the firearm wasn't cleaned promptly.

Since most cartridges in the late 1800s were black powder and had to be cleaned with hot water anyway, the primer wasn't really a problem.

Also mercury supply was often difficult in wartime, so most militaries would tend to keep away from it.

Just what I can remember off the top of my head - it may not be totally accurate. If it isn't, please enlighten me.

It appears you're more knowledgeable about the chemical composition than me....which wouldn't take much! I'll have to defer to your thoughts unless someone better informed than both of us chimes in. I had always read and heard the mercuric priming was the reason for so many pitted bores from the early smokeless powder days. Evidently it was potassium chlorate? That goes to show one shouldn't take as gospel what has been put forth by gun writers for decades, as if I didn't already know that. Maybe all of them didn't write that but a pile of them did!! That and my ignorance of chemistry was cause for my thought.

When I mentioned the late 1800's I was referring to the introduction of smokeless powders, not the still extant black powder cartridges.

Probably most of the rust from the early days was bad cleaning. The ignition residue of BP is supposed to be quite corrosive, but they should have known that from the 1300's on (in Europe at least).

I'll leave it for more knowledgeable people to tell us when Potassium chlorate (or perchlorate) became useful.

AS I said, it wasn't a problem with black powder, because the best way to clean black powder arms was to use lots of hot water, and coincidentally that's a great way to get rid of potassium chloride (and sodium chloride).

You are all forgetting that blackpowder contains salt peter, or potassium nitrate, it leaves a salt like residue, that will and does rust a bore pretty quickly. It is also used to preserve meats.
Mercury attacks brass, making it brittle, just like lead attacks aluminium. Both cause oxidation at faster than normal rates.
Corrosive primers also contained salt like chemicals that would rust a bore, but took longer than black powder to start the damage due to the fery small amount left behind.
Hope this clears up a few things.

Cheers.