OAL off the throat... I know, I know...

Discussion in 'Reloading' started by moredes, Aug 3, 2007.

  1. moredes

    moredes Member

    May 5, 2002
    There seem to be several recommendations about setting bullet OAL off the lands and grooves. Most say anywhere from .002" - .010" somewhere, closer being "more ideal".

    There's a fairly well known riflesmith who says anything between .005 - .050" will do (point oh five oh). He says the distance of the 'jump' from the casing to the throat isn't very important--all that really matters is that the bullet's axis doesn't waver from its' "concentricity" as it goes from casing to bore. That is to say, so long as the OAL allows the bullet to contact the bore while still truly aligned in the casing as it was reloaded, the 'at rest' distance (OAL) off the lands and grooves doesn't matter. Then again, he's not (and never has been, to my knowledge) a competitor. But his rifles shoot like lasers.

    What do ya'll think?
  2. BountyHunter

    BountyHunter Writers Guild

    Jun 13, 2007
    Horse puckey.

    Each gun is a beast unto its own and each bullet is the same.

    If you are loading a magazine fed gun, load to the max OAL for the mag and start from there. Come out at .010 intervals until you find where it shoots best (after you have worked powder). That way you know the round will fit into the mag and you find the spot it shoots the best. Then work at smaller intervals if you want to tweak it.

    if loading for a single shot, two rules that are acceptable 98% of the time.

    1. VLDs normally shoot best into the rifling as much as .020 or so.
    2. FB and non VLDs normally shoot best with some jump.

    Start the VLDs (Berger, JLK, etc) about .030 into the lands and work out at .010 intervals.
    Start the non VLDs (SMKs) and FB about .010 into the lands and work out.

    Now if anyone thinks that seating depth is not important, just load up 6-8 sets of 5 rounds (same and best powder charge) starting .030 in and coming .050 out. You will see the groups open and close somewhere in that mix.

    Barnes has bullets that are especially made to shoot with a .050-.070 jump for mag guns.