A good 9-10 pages of Stevens' dissent is spent looking at all the different proposed languages set forth for the 2nd amendment and then concluding that because Madison chose not to base his language on proposals that more explicitly protected civilian usage, that he MUST not have had any intention to protect civilian usage.
This statement is not based on any historical evidence whatsoever. Stevens is apparently capable of reading the mind of a man who's been dead a VERY long time. I'm impressed.
There are any number of reasons Madison might have chosen this particular formulation. It is, for one, far simpler and more elegant than other proposed variations. For all we know, this could have been his reasoning. He could have felt that additional commentary on what exact usages were protected was superfluous since he had already stated that the right "shall not be infringed".
Attempting to discern what was intended by what was not said is always dangerous and claiming to be able to read the author's mind to determine his underlying motive for NOT saying something is shear hubris. (And yes, Scalia does a bit of this as well, but it's tangential in Scalia's argument and is a fundamental cornerstone of Stevens' dissent.)