I think more recipes for ammunition should be ON by default (or recommended in its description) when K2's more realistic weapon options is ON (which is its default) and aluminum MOD is in use.
Otherwise rifle magazines can not be crafted until copper processing is researched.

Oh additional recipes still require at least one copper plate!!

Hmm so I concluded that Lead does nothing to do this with:)
Aluminum just makes it difficult to use rifle magazines.

Ah, thanks for raising this. It is indeed specific to the Aluminum mod. Do you think I need to update this to allow rifle magazines to be made without copper, earlier, or is it a fun/good challenge to get to rifle magazines? If it's a good thing, I can just add a tech dependency, otherwise I'll change around some recipes to balance it a bit.

I think making it a challenge to craft rifle magazine is ok but also think it good to add some warning/advice for K2 players to disable more realistic weapons option if one feel it difficult.