This is REALLY cool!
I always assumed that the magnetic surplus ammo I had was a copper and iron alloy, rather than a sandwich.
Makes me wonder about barrel life….of course like people talking about extractor wear when shooting steel case ammo, the fact that an extractor (or a barrel) is hardened steel (and in some cases chrome lined in rifle barrels…does anybody chrome line pistol barrels?) the wear is more-than-likely academic under normal shooting volumes.
Luckygunner did a big test in 2013 with AR15’s.
http://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/
Basically it boils down to, with the money you save shooting steel cased bi-metal ammo you can replace the barrel and other parts and still save money.
And on the subject of chrome lined pistol barrels, I don’t think anyone does. But you probably could get them Melonited.
Also Weer’d, remember that pistol cartridges are a lot lower in pressure and velocity compared to rifle cartridges.
Oooh, I love seeing some real material science applied to the bullet jacket debate.