Re: 338 edge, lapua or RUM?
Cheaper brass, but correct me if Im wrong but the Edge is a much much higher pressure round, so Id guess you would get less than half the life of a LM case.
It does lend itself to a budget cartridge though in the fact that you can easily build one off a standard action.
Dies are a wash, Lapua mag dies dont cost any more than any others.
Bullets wash.
Powder wash.
Brass price is the big hurdle to get over with the LM, but if you find once fired for $1.00-1.50 case, and you can use it 15 times its not too bad.
Obviously you CAN make any of them as accurate as the other, the LM has however proven itself enough to be widely used by military's all over.