Yes you are correct but if his intent is to use it at a range that does not allow steel core they will do the magnet test and if it sticks they will not let you use it no mattet how hard you try to convince them.
A fast way to find out what the core is is a bolt cutter. Or you can pull the bullet and hold the bullet with a vise grip and heat it with a torch the lead that hold the steel core in will meld and then you can get at the core and if it is lead it will all melt out.
On Chinese ammo, if the bullet is Boattail shaped , it is Steel core. If flatbased, Lead core center. So you can just pull one bullet. I would think All SC 762x39 is boattail shaped.
Being bxn it is almost certainly steel cored. This stuff is readily, and affordably, imported into Canada but not the US.
I personally wouldn't shoot it, being relatively collectible.
A forum community dedicated to all firearm owners and enthusiasts. Come join the discussion about optics, makes, models, gunsmithing, styles, reviews, accessories, classifieds, and more!