I believe the M43 is a designation that they use to describe the ammo, so my guess is yes, it's all steel core if designated M43...
I'm just sitting on the fence on this ammo as I had ONE VERY BAD experience with it last year... I shot a pile of it through my Valmet when I was told it was NON-corrosive by the seller... 2 days later, my rifle was a FRICKEN disaster! RUST everywhere... I cleaned and cleaned, I poured hot water everywhere, I cleaned again... What a pain...
So, as you can imagine, I am just a LITTLE hesitant to buy some more, EVEN though at $169 delivered, it's an awesome price!!! hell, what would shipping cost them, kinda makes you wonder what they pay for the case huh???
Cheers
Jay