Due to the recent flurry of posts and pm's, I am revising my previous statement.
I had planned on not restricting magazines so that people who only own HAND-winding high capacity magazines could participate. NOT so that people could use huge auto-winding magazines for weapons they have no business being on.
So, to clarify: low, mid and high capacity magazines may be used as long as they do not feature an auto-winding mechanism.
The exception to this is any weapon who's real world counterpart utilizes a box magazine (m249, m240, RPK etc).