A good M-4 type with an A.C.O.G., Holosight or Aimpoint, and you're well armed.
A properly placed round of M193 ball will kill anything you need to kill, and you can carry a helluva lot of them for the same weight as a small handful of 7.62X51.
I didn't fight to defend your freedom so you could vote to take away mine.
"A man who has nothing for which he is willing to fight, nothing which is more important than his own personal safety, is a miserable creature and has no chance of being free unless made and kept so by the exertions of better men than himself.
John Stuart Mill."