Ok so first off I've been loading rifle handgun and shotgun for over 15 years, but i've never loaded belted magnum calibers. just got a 300 win and have some questions.

#1 how many times can you load the brass i've heard 2 or 3 times then some guys say 6 or 7 times? my thoughts were I have 300 pieces of once fired brass I was going to full lenth size it for the first reloading shoot it threw my gun then just neck size it 3 or 4 more loadings.

#2 has anyone used H5010 in a 300 win I've got some and I talked to Hodgon and the guy i talked to said fill the case just short of a compressed load with whatever bullet grain of my choice and shoot it up it would be comaprable to shooting a 30/30. ???  good cheap practice ammo?

#3 what powder do you use, i've read alot about Imr 4350

thanks for any input

I load a .300 Weatherby belted case and if I full length resize with die contact to the shellholder I only get 4 loadings before case stretching makes the case unsafe. The stretch mark ring inside the case  just forward of the belt is obvious and can be felt and seen. Either buy a case headspace gauge such as Hornady's http://www.cabelas.com/prod-1/0056486216602a.shtml
  Or adjust your sizing die to not push the shoulder back when sizing.
 I've got an old chart from the net called "Cross-reference chart for Military surplus powders" and it lists 5010 using 180 and 200 grain bullets in .300 Win Mag. I haven't tested any of the loads but it says 72 grains of 5010 gives 2300 fps with 80 grains giving 2700 fps. The data is the same for both weight bullets. Some shooters over on "Long Range Hunting" forums have discussed using surplus powders.
http://www.longrangehunting.com/forums/