setting up new brass?

Discussion in 'Reloading' started by dmproske, Oct 19, 2008.

  1. dmproske

    dmproske Well-Known Member

    Mar 2, 2008
    Been loading for a little bit for pistol. Going to start loading rifle so I can feed my expensive 300 rum. Got a set of neck size dies for it. Neck sizing once fired cases from my rifle makes sense for better accuracy. But how do I set up factory fresh brass?

    If I work up a load using my fired neck sized cases, wouldn't that load group differently using factory sized brass?
  2. Varmint Hunter

    Varmint Hunter Well-Known Member

    Dec 26, 2001
    I'd just shoot the factory brass as-is. If you only have neck sizing dies you will likely run into a problem with brass that chambers tightly after very few reloads. Especially if you load the RUM at its potential.

    Just a thought

  3. loaders_loft

    loaders_loft Well-Known Member

    Feb 11, 2008
    I normally use Rem or Win brass, which needs to be full length sized before the first use.

    Even if you normally neck size your brass, you'll eventually need to FL resize them anyway, as Varmint Hunter stated above.

    If you intend to hunt with the neck sized rounds, chamber each one before you go hunting, to make sure they all fit.
  4. bigg_sexy1

    bigg_sexy1 Well-Known Member

    Dec 27, 2007
    Yes definately FL size the brass before you reload it, a friend of mine just neck sized and the reloaded a bag of bulk Rem Brass, he had 2 rounds that would not chamber.
  5. boomtube

    boomtube Well-Known Member

    Oct 8, 2007
    "If I work up a load using my fired neck sized cases, wouldn't that load group differently using factory sized brass?"

    Very little, if any.

    But, sizing new brass is cheap, you have the tools to do it, it's easy to do and insures each neck is the same. Why not do it?
  6. kraky2

    kraky2 Well-Known Member

    Jan 6, 2005
    I usually find that big cases like the 300 rum and many magnums shoot about 50 fps slower when loaded virgin compared to the exact same load in fireformed brass. Depending on the gun that can be significant....or not at all.
    I don't spend alot of time running virgin brass through any sizing die. You won't change much about the brass because it is already at minimum spec. You will get allthe neck tensions a bit more consistant.
    All I do with virgin brass is chamfer the case mouth with a low angle deburrer, run a bore brush on a drill into the case neck to remove the "scale" that's usually there from the last factory cleaning of the brass, and plunge them over a lyman m die.
    The rest of the good prep work for me comes after the first firing.