7mm-300 win issues ?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by 300stw, Feb 23, 2014.

  1. 300stw

    300stw Well-Known Member

    Dec 30, 2004
    i have a 7mm-300 in a lilja barrrel, gunsmith used a reamer with .312 neck
    i have to turn a lot of brass off necks to get a bullet to slide in a fired case, i was setup for a .316 neck, on my last 7-300,

    now i wondering easiest way to get a .316 neck in this barrel, i dont like the .312 neck and how thin the necks are on the brass,

    shooting my old brass in this new chamber has pressure issues, and ok accuracy,

  2. RockZ

    RockZ Well-Known Member

    Mar 10, 2006
    Should be able to get the smith to ream it to .316 with a throating reamer .

  3. Petersen

    Petersen Well-Known Member

    Apr 30, 2007
    Make sure your brass are properly annealed and you may have the 'donut' on the inside of the neck shoulder junction that is common when you neck calibers down. These can cause pressure issues and spikes and accuracy problems. Just a thought before you think paying someone to machine on the barrel will fix it. I think with some proper brass work and tuning you will be ok.

    I experienced some of the same issues with my 7/300 before I figured it out and I had turned way more brass off the necks then what was necessary. I had them annealed and my pressures went noticeably down. I then used a round file to remove the donut and it has been smooth ever since...

    If your neck is .312 I think a .12 wall thickness should clear easily with properly taken care of brass.