When did the domestic manufacturers of shotgun ammo/shells start using brass-plated steel for the rim/base of shotgun ammo? I'm not really into shotguns and shotshell ammo like I am for rifles and handguns; I only own a few shotguns, and shoot them rarely, as I don't hunt much anymore and most clay pigeons never had much to fear when I was around. I've never reloaded shotshells, nor have any of my friends.
Have the manufacturers been doing this for a really long time, and I just assumed the shells were brass due to their appearance, or is it a fairly recent change? I have some premium buckshot ammo that I know is over ten years old, and the rim/base of these will stick to a magnet, so I'm assuming it was farther back than that.
Thanks for any/all help on this subject. Just wondering how far out-of-date I am on this.... hoping it is "years" instead of "decades".