Looking at a McMillian lefty stock for two piece WSM metal. My lefty Featherweight WSM has one piece metal. I have found a factory two piece bottom metal. Will my mag box assemby work with just the 2 piece metal or do I need the whole two piece assembly?

As far as I understand it, the mag box is the same, but the stock inletting is different.
I have 2 rifles that were originally the 2 piece, I swapped them out for the one piece, the inletting needed minor alteration for them to fit.
Maybe someone knows more precise info that will be more helpful, I've never gone the other way.
May I ask why you would want to ditch the one piece bottom metal?
It's stiffer than the 2 piece.

Cheers.

I assume you mean to say the stock you're looking at is already inletted for the two-piece system. If so, then simply obtain the two-piece assembly, add the center screw (snug, NOT TIGHT) and your mag box should be just fine.. (NH rifles)

Thanks guys. Yes the stock is inletted for two piece metal. Just need to make sure it fits the WSM dimensions. I heard I may have to open up the ejection port some.