Rule of Thumb?

Discussion in 'Reloading' started by DannoBoone, Apr 13, 2009.

  1. DannoBoone

    DannoBoone Member

    Messages:
    20
    Joined:
    Dec 10, 2007
    Seems like there is a rule of thumb regarding groups. All factors
    being consistent in case prep, loads, OAL, etc., is there a rule
    of thumb to use for tightening up groups?

    If memory serves correctly, one can try OAL adjustments or powder
    adjustments if a clover-leaf group is a bit large. And an
    adjustment if there is an occasional flier in an otherwise tight
    group.

    Is there actually this "Rule of Thumb", or have I just been
    dreaming?
     
  2. nheninge

    nheninge Well-Known Member

    Messages:
    284
    Joined:
    Oct 20, 2008
    no rule of thumb, but

    the sticky post on seating bergers is a great start for all vld bullets

    All things being held constant, theoretically there would be a one hole group at 1000 yards, but this isn't the case. So many variables. Start with your equipment. Barrel type (custom/factory will make the biggest difference in tightening up your groups, then you can monkey around with OAL , neck tension etc. If you have a factory barrel, then that will be the biggest limiting factor in your groups even with PERFECT ammo, although some factory barrels are better than others.

    Start by examining your goals (what do you need the rifle for)...., then your equipment (rifle, scope, scope mounts, stock etc)..., then your loads and see where you can make the most improvement for your dollars/time spent. An new barrel with average loads (irregardless of COAL) may be the best group tightener you have ever seen!!!
     

  3. Michael Eichele

    Michael Eichele Well-Known Member

    Messages:
    3,829
    Joined:
    Jan 6, 2003
    A few things I have found for tightening up groups. the only rule of thumb is consistency, consistency, consistency.

    After that, make sure your neck tension is the same from round to round. Also I have adjusted groups by making the necks a bit tighter or a bit looser in .001" increments. Sometimes you must anneal your case necks to get consistent neck tension. Always at the very least brush out the necks after each firing, uniform primer pockets, deburr the flash holes, keep the necks the same length, if you neck turn then watch for do-nuts, minimize runout.

    Most flyers come from either shooter error or the barrel is undergoing some heat issues. If youre shooting on bags and the rifle doesnt ride the bags consistently, you can get flyers. If using a bi-pod and you dont hold it just right and let her recoil differently, you can get flyers. If you apply too much grip or just plain inconsistent grip pressure or cheek pressure or even shoulder pressure, you can get flyers.

    When using a properly developed load and the procedure is consistent, flyers are rarely the result of the load. It is ussually the nut behing the trigger.