.308 Load, and Optics for Long Range M1A (M21)

Discussion in 'Long Range Competition' started by G-gear, Mar 14, 2010.

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  1. G-gear

    G-gear Well-Known Member

    Jan 27, 2008
    My Springfield M1A (M21) can group well under an inch with 168 SMKs, Lapua brass, CCI 34 primers, and 40.5 grs. of H4895.
    I haven't tried past 100 yards yet, but, since I've been looking at buying a Zeiss Conquest Rapid Z 800 or Z 1000 scope, the dope on their website has caused me to recently write the following:

    'Been doing some hunting for the best scope for my Springfield M1A (M21).

    Springfield Armory Rifles


    Both are around $925
    And both are 4.5-14x50

    Note: Please enter your information into our Rapid-Z Calculator to ensure that you make the best possible reticle selection
    based on your caliber, bullet, hunting conditions and location.

    According to their calculator for the Rapid Z 1000 (designed for the .308 Match ammo):
    This IS the value for .308, Sierra 168-gr. MK (BC =.462),
    Velocity: 2,550 fps,
    Elevation: 4,500 ft. ASL
    Temp: 80 degrees F

    The Rapid Z 1000:
    With their calculator, and the scope power ring set to 11.87 (12 power):
    They say to zero dead-on at 500 yards with the Bar 5. (Bar 5 is the center crosshair.)
    At Bar 1, the bullet will impact at 154 yards (and you can zero at 154 yards with Bar 1, on 12 power).
    (Bars 1 - 4 are above the center crosshair Bar 5.)
    Bar 2 = 224 yards
    Bar 3 = 316
    Bar 4 = 406
    Bar 5 = 500
    Bar 6 = 595
    Bar 7 = 692
    Bar 8 = 791
    Bar 9 = 892
    Bar 10 = 993 yards
    This is seemingly unbeatable.

    Now, with the Rapid Z 800:
    With the M1A, same load, they say to put the power ring at 14 power.
    Sight in at 1.77" high @ 100 yards for a 200 yard zero (Center Crosshairs - call it Bar 1).
    (All other Bars are below the center crosshairs - Bar 1.)
    At Bar 2 (an unmarked bar), bullet will impact at 295 yards.
    Bar 4 = 395 yards
    Bar 5 = 495
    Bar 6 = 596
    Bar 7 = 698
    Bar 8 = 800 yards

    I know it's not a 1,000 yard reticle - but 'tis rather versatile anyway...

    :rolleyes: So, I'm deciding on which to choose.
    More field of view at 12 power with the Z 1000, than at 14x on the Z 800.
    And the Z 800 is intended for other calibers; but, look what it does for the .308!

    But, if you definitely need it backed-off at the lowest 4.5 power also, then the Z 800 will work for both close-quarter, and long-range work.
    At 4.5 power, just use the center crosshairs for 0-300 yards - then for precision: Zoom to 14x for 200-800+yards.

    Q. What would the Z 1000 do at 4.5 power? - when it is set up for all ranges (100-1000) at 12 power?
    A. Dead-on at 500-yards ONLY - Center Crosshairs - Bar 5.

    Maybe we can't have our cake, and eat it too. :D

    So, for me, THE DECISION IS: Z 800 !

    The Z 800 is more traditional and more useful under stress. Your short-range field of view (FOV) and accuracy (at 4.5 power) could mean everything.
    I'd stress more over the up-close and personal - than sweat the remaining 200 yards down range to the magic 1,000 marker.

    But, for a dedicated LR benchrest set-up - or if you don't mind having it at 12 power all of the time, the Z 1000 scratches the 1,000-yard itch.

    [email protected]

    You can check-out their reticles here:
    Zeiss Rapid Z 1000
    Zeiss | 4.5-14x50 AO MC Conquest Riflescope | 52 14 90 9973

    Zeiss Rapid Z 800
    Zeiss 4.5-14x50 800

    LRB 7x50 laser rangefinder binoculars


    Almost. :)

    Last edited: Mar 14, 2010