+57 (second amendment interpretation 36)

First we have the "well regulated" suggesting trying to make the militia as efficient as armies of that time.

Second, we have the use of "being" taking things away from expressing continuity to refer to the militia itself and instead stops at referring to its status.

Third, we have things taken away from expressing shared root coming from an always existent militia, by having "security" referred to as in its status of being a separate thing that can have its own degree of quality not necessarily as that provided by the militia.

Then, we have all that connected to the empowerment the arms clause leads to.   

It all seems to fit the purpose being effectiveness and shows nothing at the depth of the mere existence of the militia itself being a purpose behind the amendment. Unless we are reading one of those jokes that sets your mind at one meaning then surprise you with a much less expected one, does this look like how things should reasonably be expressed if the mere existence of the militia was a concern? They even could have suggested the mere existence of the militia being a purpose much better with less of the same expression by writing "necessary" instead of the whole "necessary to the security of a free state".