Lead Angle for 7mm Berger 180's

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by SidTheKidd, Feb 21, 2011.

  1. SidTheKidd

    SidTheKidd Well-Known Member

    Messages:
    156
    Joined:
    Nov 21, 2008
    What sort of lead angle are you guys using on your reamers for the 7mm 180 VLD's? I was thinking I could use a throat reamer in my rifle in order to match up the lead angle in my rifle for the VLD's.
     
  2. AZShooter

    AZShooter Well-Known Member

    Messages:
    2,075
    Joined:
    Dec 12, 2005
    My Pacific tool and gauge 7 rem mag reamer has a 1 degree 30 minute throat angle. Worked great with the 180 VLDs jammed into rifling.
     

  3. BryanLitz

    BryanLitz <b>Official LRH Sponsor</b>

    Messages:
    633
    Joined:
    Mar 8, 2007
    My thinking on this has always been that the leade angle doesn't matter. Why? The corners of the rifling where the bullet first contact washes away (erodes) during barrel break in so that by the time you have 50 rounds thru the barrel, the angle is something different from what you calculated and cut.

    I don't know of any specific angles for leads that have produced better or worse precision with VLD's (or any other bullet designs for that matter) over the life of a barrel.

    My thinking is to go with a relatively shallow angle because it's going to erode to something shallow anyway. By starting with a shallow angle, break in requires less rounds.

    -Bryan
     
  4. Broz

    Broz Well-Known Member

    Messages:
    8,637
    Joined:
    Feb 3, 2007
    And what would you suggest thet shallow angle be?

    Thanks!

    Jeff
     
  5. BryanLitz

    BryanLitz <b>Official LRH Sponsor</b>

    Messages:
    633
    Joined:
    Mar 8, 2007
    Keep in mind I haven't paid close attention to this, so the following is my perception which may not be accurate...

    I think 1.5 degrees is considered shallow, and 3 degrees or more (which is sometimes used for VLD bullets) is considered steep.

    More important than the leade angle, is the throat length IMO. Throat length will determine how far the bullet is seated into the case which is important for:
    1) Internal case capacity
    2) base of the bullet interfering with the 'donut' at the base of the case neck
    3) will the round be mag length feed-able and be able to reach the riflings.

    -Bryan
     
  6. Broz

    Broz Well-Known Member

    Messages:
    8,637
    Joined:
    Feb 3, 2007
    Thanks Bryan,

    I am getting ready to order a reamer for another 7mm-300 win I am building. I have plenty of room in the mag box with the use of a Wyatts box or the Seekind DMB I have. This rifle will be for the use of 180 Bergers only and it will have a 1 in 9 Hart with 6 lands. I have thought of placing the top of the boat tail right at the bottom of the neck for greatest case capacity, so only the boat tail in into the case powdr area. Then have the reamer ground for it to be just off the lands.

    Any input you have will be greatly appreciated.

    Thanks!

    Jeff
     
  7. BryanLitz

    BryanLitz <b>Official LRH Sponsor</b>

    Messages:
    633
    Joined:
    Mar 8, 2007
    Jeff,

    I agree with your plan for throat length, except I would leave a little room between the bullet and riflings in case it likes a jump.

    -Bryan
     
  8. Broz

    Broz Well-Known Member

    Messages:
    8,637
    Joined:
    Feb 3, 2007
    Good thought! The last one I did shot good with them close to lands but when seated off the lands (.115" to fit in the factory box) they shot extremely well. I want to get this reamer perfect so I will add another .030"~.040" throat. Any farther and I would start to worry about not enough bullet in the neck since this is a hunting rifle. Neck length is .230"~.240"

    Jeff