You don't do "links" and Remington nor any other ammo manufacturer did "zink" either.
If you want the appearance of credibility, I would suggest at least spelling the subject in question correctly.
'Necro-Posting' is what internet snobs call responding to an old thread.
Reviving ne that was essentially dead.
(like this forum with it's abundance of 'Keyboard Commandos' and internet snobs...)
Only the guys roaming around looking for someone/something to complain about b!tch about 'Necro-Posting' and spelling/grammar as long as the post is even marginally legible...
It's been my experience that it's usually some lonely fat guy in his mom's basement, setting in his under ware looking for a way to make himself feel 'Superior' on the internet,
Not realizing the rest of us just don't care...
Besides, with the small amount of traffic on this board, a year later the thread is still on the 'Top Shelf' for people to find...
That usually means the 'Snobs' can't cut it on the popular board, so they hang out on the low traffic boards and regurgitate what they have found on other boards, correct spelling, grammar and generally are devoid of any first hand knowledge...
I find some of the best information on 'Old Threads' sometimes.
There are some guys that post up good information, then the lack of traffic drives them to other places.
You have to 'Drill Down' sometimes, past the 'Regulars' that post up anything and everything they come across someplace else and try to duplicate here (usually poorly) and present it as their 'Own Idea' or knowledge without research...
That's how most of the 'Myths' get repeated until they are 'Folk Lore' and then they are REALLY hard to correct because people have heard them in so many places so many times!
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The jacket material is probably a Tin/copper alloy since there was a shortage of Copper during WW-II.
Real tin is NON-Magnetic when mixed with as little as 10% copper, and it's soft enough to grip the rifling without much damage to the barrel, and was used extensively throughout the world during both world wars.
The core is probably lead since the US didn't have a shortage of lead during WW-II, but both were used as cores during WW-II.
Being non magnetic, I'd say lead core...
The RA is probably 'Remington Arms', but there were some military manufactures in 1940, and I don't know all their head stamps...
Like 'Rock Island Armory' which is sometimes abbreviated 'R A' or 'R I'...
Lake City Armory is always LC currently, but during WW-II some of the head stamps were 'L A' for 'Lake City Armory'...
So I can't give a definitive answer on that head stamp since I wasn't there in 1940...
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The jacket isn't Zinc.
Zinc was a war material we had shortages of during WW-II,
And zinc would have corroded with nothing but air contact by now...
Zinc is a fairly reactive element with oxygen and other corrosives, that's why it's used in batteries and other reactive situations.