The think about out Constitution was that it was written over 200 years ago. Words mean things. Using In Noah Webster's "A Compendious Dictionary of the English Language," published in 1806 - the folks at TheWashingtonTimes have helped everyone out. Check it out.
"People" were "the commonality, as distinct from men of rank," and "Right" was "just claim; immunity; privilege." "All men have a right to secure enjoyment of life, personal safety, liberty and property," he wrote. Thus in the language of Webster's time, "the people" meant individuals and individuals have "rights."
"Keep" was defined as "To hold; to retain one's power or possession; not to lose or part with.... To have in custody for security or preservation"; "Bear" as "to carry" or "to wear; name; to bear arms in a coat"; and "Arms" were defined as "weapons of offense, or armor for defense and protection of the body."
Only civilians would "bear arms in a coat" - soldiers carried muskets in their hands, while officers carried pistols in holsters.
Thus the words "keep and bear arms" suggest a right to hand-held arms as a person could "bear," such as muskets, pistols and swords, but not cannon and heavy ordnance that a person could not carry.