seating depths affect on accuracy?

Discussion in 'Long Range Hunting & Shooting' started by rufous, Jul 21, 2003.

  1. rufous

    rufous Well-Known Member

    Messages:
    174
    Joined:
    Jul 17, 2001
    I too am having some problems with horizontal stringing. I am shooting a 7mm Rem Mag with the 160 Nosler Accubond. I have tried varying the powder charge and the seating depth. I am pretty happy with the load I have come up with (8 groups averaging 0.85 MOA- 3 of those groups were at 400 yards) but the larger groups are due to a shot off to the left or right. I was surprised by a comment on a different post that seating depth can have an affect on horizontal stringing. I had thought that powder charge and seating depth mainly affected vertical and that horizontal was mainly wind or gun handling or parallax. So far it seems that my gun is shooting this bullet best at touching the lands or 0.010" into the lands. Same basic accuracy at both. I have tried 0.010, 0.020, 0.025, 0.030, and 0.040" off the lands also. I have not tried 0.020" into the lands though. Maybe that would be even better? I did seat a bullet long (0.030" into the lands) and chambered the round just to see if the bullet would be pushed back into the case neck. It did not move. Neck tension must be farely high. I am using an RCBS competition full length sizing die, not the Redding bushing dies. Do you think there would be any point in trying 0.020 or 0.030" into the lands? Rufous.
     
  2. H-BAR

    H-BAR Well-Known Member

    Messages:
    235
    Joined:
    Apr 18, 2003
    If you have a windage adjustable mount make sure that it hasn't come loose or that it is not working around!!! I had problems with the Leupold long range base on my gum!!! The windage screws where they hold onto the dovetail milled into the rear ring kept working loose due to extreme recoil. I bought a Ken Farrell base and Warne Maxima rings so hopefully the problem is resolved!!!
    Well that is what I get for mounting a heavy scope on a cheesy base and rings!!! A friend of mine said I should have used loctite on the windage screws but I feel that this would be a poor fix due to the screws being cemented in place and the ring still moving betwwen the screws. All it has to move is .001 of an inch to spread your group at 1000 by ten inches over what it would normally be!!!