Trijicon TA31F; Ranging/Ballistics Question.

GTS197GTS197 New MemberPosts: 18 New Member
I need to zero my AACOG, which has the reticle's BDC set for meters; 100-800. The problem is, the range I shoot at is only set up for 100 yards.

Where will I need my POI to be at 100 yards, to achieve a 100 meter zero?

Ammo to be used is 55gr, .223/5.56 at approx 2950-3000 fps.

Nikon's ballistics program indicated hitting .03" low at 100 yds, but that was with a velocity of 3270 fps and the sight line being 2.5" above the bore line (which I believe it already is). If this is accurate, there really isn't much difference between yards and meters, with a 100 yard zero...approx .1" low at 400 yards, .2" low at 800 yards, etc...(theoretically, of course.)
In ten years nobody will remember the details of caliber, stance, or tactics. They will only remember who lived.

Replies

  • knitepoetknitepoet Senior Member Posts: 18,869 Senior Member
    Since you're talking about a low magnification "combat" sight, I doubt the ~30 feet difference between 100ys and 100M would be outside the groups you'll be shooting anyway.

    I can tell you from personal experience though, ANYTHING, other than shooting YOUR particular rifle-ammo at distance is a guess
    Seven Habits of Highly Effective Pirates, Rule #37: There is no “overkill”. There is only “open fire” and “I need to reload”.


  • GTS197GTS197 New Member Posts: 18 New Member
    Good call. It's not mounted on a sub-MOA bolt gun, either. I guess the difference would be negligible.
    In ten years nobody will remember the details of caliber, stance, or tactics. They will only remember who lived.
  • BigDanSBigDanS Senior Member Posts: 6,803 Senior Member
    It's very close to a 10 % ( 100 meters = 328 ft) difference in distance, but at 100 yards it will be negligible.

    If it is sighted in meters at 200 yards ( 600 ft vs 656 ft ) there is a 20% difference, and at 300 yards a 30% ( 900 ft vs 984 ft ) difference. It would shoot high at longer distances if you used the meter marks. To be sure you would need to do groups at the distances , with the loads and confirm group size and POI.

    D
    "A patriot is mocked, scorned and hated; yet when his cause succeeds, all men will join him, for then it costs nothing to be a patriot." Mark Twain
    Alcohol, Tobacco, Firearms and Explosives.... now who's bringing the hot wings? :jester:
  • GTS197GTS197 New Member Posts: 18 New Member
    BigDanS wrote: »
    It's very close to a 10 % ( 100 meters = 328 ft) difference in distance, but at 100 yards it will be negligible.

    If it is sighted in meters at 200 yards ( 600 ft vs 656 ft ) there is a 20% difference, and at 300 yards a 30% ( 900 ft vs 984 ft ) difference. It would shoot high at longer distances if you used the meter marks. To be sure you would need to do groups at the distances , with the loads and confirm group size and POI.

    D

    The BDC is graduated in meters, so that's would I would like to zero it at. I just need to try to find the extra 9 yards to stretch it out to 100 meters for the zero. If I can't...yards it is.
    In ten years nobody will remember the details of caliber, stance, or tactics. They will only remember who lived.
  • knitepoetknitepoet Senior Member Posts: 18,869 Senior Member
    My heavy barrelled AR will out shoot all my current bolt guns and if a load shoots 1 MOA, it get's scrapped and I try something else Even my light barreled one will shoot right at to just over MOA.

    AR's can be QUITE accurate :tooth:
    Seven Habits of Highly Effective Pirates, Rule #37: There is no “overkill”. There is only “open fire” and “I need to reload”.


  • GTS197GTS197 New Member Posts: 18 New Member
    I know they can shoot better than I can.

    I'm running a chrome lined 1:9 with factory loads. Nothing special.

    I'm sitting on a stripped lower, which I'll be building into a HB varminter.
    In ten years nobody will remember the details of caliber, stance, or tactics. They will only remember who lived.
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