I think you're totally misreading Coburn's initiative.
He's talking about $681 billion in savings over ten years!. That's 1% of the current defense budget ($651 billion).
What's more, the specific savings are perfectly reasonable. For example, is there any question that the military has more admirals and generals than it can possibly use.
Coburn is making a point that the military budget can be reduced and the GOP leadership should be prepared to include minor (and appropriate) military cuts in exchange for major cuts elsewhere.