7mm-300 Win Mag

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by HillbillySniper, Sep 9, 2018.

  1. HillbillySniper

    HillbillySniper Well-Known Member

    Messages:
    163
    Joined:
    Jan 24, 2010
    Im building a 7mm-300 win mag on a rem 700. I want to shoot 180gr Bergers vld with Norma brass. Is anyone using this combination? What is your fired case neck diameter, your loaded round neck diameter and your re sized neck diameter? Im trying to figure out what my reamer neck clearance should be? Does anyone have a reamer setup for the 180? Any info regarding the round would be greatly appreciated!
     
  2. rfurman24

    rfurman24 Well-Known Member

    Messages:
    1,463
    Joined:
    Aug 29, 2010
    My loaded necks with Norma or Nosler brass were .313 I cut my chamber for .316. I see no reason to mess with fire forming by creating a different angle shoulder. The bullet is going to like a certain velocity node and going to a 30 degree shoulder will not get you to the next higher node. The only thing it will do is make you have to fire form. Just run the straight 7-300, neck it down in two steps, load bullets, and shoot. My reamer was cut for 180 Hybrids so if you choose a different bullet you will most likely need more freebore. You can call Dave Kiff and mention my reamer and make any freebore adjustments necessary. My print is on file with PTG the number is 41753. Both of my barrels had an accuracy node around 3165fps out of 28" Bartleins. Both were about 1-1.5 grains below any indication of pressure.