I've just started reloading the 50. I picked up the Lee 50 bmg reloading combo from Midway for just over 150 (about a year ago). The press is good enough and the dies will make as good as any other standard 50 dies.
The other 50 presses and dies cost a least 3 times as much, if the Lee wasn't available it might be hard to justify a reloading setup compared to buying a few hundred rounds
I got all the componants I needed from Pats Reloading although there is usually a 2 month wait and some stuff goes out of stock, they are fine folks to deal with.
The costs as I rememberare;
Primers, CCI #35 $25-30 a hundred.
Bullets, I'm using pulled AP (695 gr), you can get pulled tracer etc a little cheaper but I learned the hard way about tracers myself.
They cost $0.40 -.45 each. new bullets run $0.70 to several dollars a piece. You need to size pulled bullets or buy them sized.
Powder, I'm using virgin 5010, cost me $80 per 8#, Ithink it's up another $10 plus now, @ 220 gr per load thats approx 31 loads per lb Or $0.26 per round. You can get pulldown WC860 for less or commercial stuff for more.
So It costs me $0.90/95 per round not including brass.
Brass costs ).60 to $1.00 each for once fired military stuff. You have to inspect each case and look for expansion just above the base, you can see a ring inside the brass near the base were the brass is overstretched. I had a fellow trade me 100 that I won't use so don't pay (or trade)for useless brass.
It's not much different than standard reloading, got to cut the primer crimp on the mil brass and the primers come with a slight dome shape to them, seat them a few thou set in and the primers get flattened and look like any other-just bigger. Apparently if you don't seat them and flatten the dome they might take a couple strikes to set off. I've had no problem.
The 50's are a hoot to shoot.