Shot group question

Discussion in 'Reloading' started by freebird63, Sep 10, 2010.

  1. freebird63

    freebird63 Well-Known Member

    Dec 20, 2009
    I have read and printed off Jerry Teo's article on load tuning, but came away with a question that maybe someone can answer.
    Your out shooting, you have not quite found the magical load.
    So say your shooting a 300RUM and you have loaded some ammo with retumbo powder, say 200gr accubonds or even 210gr bergers. Your shooting at 200 yards, one group of 5 shots is all horizontal-what does this mean when a group is all horizontal???
    Then maybe you switch powders and try RL25 and same bullets and you have 5 shots that are all vertical-what does it mean when the groups are verticle???
    Also say there is no wind, you have your gun resting in a lead sled and your trigger is set pretty light. If your not flinching what would some of the causes be for these two groups???
    Thanks a bunch guys.
  2. Buffalobob

    Buffalobob Well-Known Member

    Jun 12, 2001
    What it means is that you have missed (or not found) the powder charge weight which gives a round tight group. Whether either of those powders will give you that group I do not know. But you should try increasing or decreasing the powder charge in half grain increments for a couple of grains and see if the shape changes.
  3. Mikecr

    Mikecr Well-Known Member

    Aug 10, 2003
    If the groups are consistently X or Y, with low ES & no double grouping or contradictive fliers, I say it's tune. A barrel tune all by itself can cause horizontal, or vertical dispersion.
    That is, you could exactly settle into a tune that causes one or the other, or both(round).
  4. strobes

    strobes Member

    Sep 9, 2010
    I got it from a different forum. In my experiens these comments are very thrue. Well, ...given that everithing else is in good order :)..

    When you run a typical ladder test your incremental shots usually string in a vertical plane.When you hit a node the vertical goes away.Very near the top end of the node your shots will go to the right on you but as you keep going they will line back up and keep going up verticaly.
    Because you were shooting 5 shots at a time you saw the typical horizontal shift as 5 horizontal shots instead of 1.
    Your best accuracy and lowest extreme spreads will both be right below the shots that went to the right.
    I always shoot facing the same direction so my shots go to the right.I have never checked to see if shooting in the other direction will string them to thre left.