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

Discussion in 'Rifles, Bullets, Barrels & Ballistics' 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).

    [COLOR=#551011]Springfield Armory Rifles[/COLOR]


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

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

    Zeiss Calculator: [COLOR=#551011]http://www.zeiss.com/c1256bcf0020be5f/Contents-Frame/46cbcef61def2b88852574f700589d31[/COLOR]

    Calculator instructions: [COLOR=#551011]http://exbalapplications.com/ZeissWeb/(S(cdcd0d55lurh5i55lo5kofnq))/data/Instructions-English.pdf[/COLOR]

    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

    Zeiss Rapid Z 1000 (Click below to see reticle):
    [SIZE=3][COLOR=#551011][B]Zeiss | 4.5-14x50 AO MC Conquest Riflescope | 52 14 90 9973[/B][/COLOR][/SIZE]
    With their calculator, and the scope power ring set to 11.8x (12 power):
    *Optimize Power for: Bar No. 10 - Distance 1,000.
    [FONT=Times New Roman][SIZE=3]They say to zero dead-on at 500 yards with the Bar 5. (Bar 5 is the Center Crosshair.) [/SIZE][/FONT]
    [FONT=Times New Roman][SIZE=3]Easier way: To zero Bar 5 @ 100-yards: [/SIZE][/FONT]
    [FONT=Times New Roman][SIZE=3]On 11[B].[/B]8x (12 power): make bullet impact 11[B].[/B]87" high @ 100 yards (above Bar 5 - Center Crosshair).[/SIZE][/FONT]
    [FONT=Times New Roman][SIZE=3]Then this will happen:[/SIZE][/FONT]
    [FONT=Times New Roman][SIZE=3]At Bar 1, the bullet will impact at 139 yards - (and you can roughly zero at 139 yards with Bar 1, on 11.8x ([U]12 power[/U]).
    (Bars 1 - 4 are above the center crosshair Bar 5.)
    Bar 2 = 218 yards
    Bar 3 = 313[/SIZE][/FONT]
    [FONT=Times New Roman][SIZE=3]Bar 4 = 404
    Bar 5 = 500
    Bar 6 = 597
    Bar 7 = 695
    Bar 8 = 796
    Bar 9 = 897
    Bar 10 = 1,000 yards
    This is seemingly unbeatable.

    Now, with the [B]Rapid Z 800 (Click below to see reticle)[/B]:[/SIZE][/FONT]

    [FONT=Times New Roman][SIZE=3][URL="http://www.bhphotovideo.com/c/product/553439-USA/Zeiss_52_14_91_9972_4_5_14x50_AO_MC_Conquest.html"][B][COLOR=#551011]http://www.bhphotovideo.com/c/product/553439-USA/Zeiss_52_14_91_9972_4_5_14x50_AO_MC_Conquest.html[/COLOR][/B][/URL]
    With the M1A, same load, they say to put the power ring at 7[B].[/B]45 power.
    [FONT=Times New Roman][SIZE=3][FONT=Times New Roman][SIZE=3]*Optimize Power for: Bar No. 8 - Distance 800.[/SIZE][/FONT][/SIZE][/FONT]
    Sight in at 1[B].[/B]77" high @ 100 yards for a 200 yard zero (Center Crosshair - call it Bar 1). [/SIZE][/FONT]
    [FONT=Times New Roman][SIZE=3](All other Bars are below the center crosshair - Bar 1.)
    [FONT=Times New Roman][SIZE=3]Watch it fall into place:
    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 and low-light capability with the power ring set at 7[B].[/B]45x with the Z 800 bullseyes, than at 11[B].[/B]8x with the Z 1000 bullseyes.
    And they say the Z 800 is intended for other calibers; yet, look what it does for the .308![/SIZE][/FONT][/SIZE][/FONT]

    [FONT=Times New Roman][SIZE=3][FONT=Times New Roman][SIZE=3]But, with the Z 1000, there [B]is[/B] more magnification (11.8x) for long distance at each Bar (stadia).

    But, if you definitely need it backed-off at the lowest 4[B].[/B]5 power also, then the Z 800 will work for both close-quarter, and long-range work.
    At 4[B].[/B]5 power, just use the center crosshairs for 0-300 yards - then for precision: Zoom to 7[B].[/B]45x for 200 to 800+yards.

    [B][SIZE=4]Q.[/SIZE][/B] What would the Z 1000 do at 4[B].[/B]5 power? - when it is set up for all ranges (100-1000) at 11[B].[/B]8 power?
    [B][SIZE=4]A.[/SIZE][/B] Dead-on at 500-yards [B]ONLY[/B] - Center Crosshairs - Bar 5. (Bar 5: bullet impacts 11.87" high @ 100 yards when set at [B]ANY[/B] magnification (4[B].[/B]5x - 14x). -Would need to test point of impact of Bars 1-4 on 4[B].[/B]5x ).[/SIZE][/FONT]
    [FONT=Times New Roman][SIZE=3]
    Maybe we can't have our [I]convenient[/I] cake, and eat it too. :D

    So, for me, THE DECISION IS: [SIZE=4][B][I][SIZE=5]Z 800 ![/SIZE]
    The Z 800 is more [I]traditional[/I] and more [I]useful [/I]under stress. Your short-range field of view (FOV) and accuracy (at 4[B].[/B]5 power) could mean everything.
    I'd stress more over the [I]up-close and personal[/I] - than sweat the remaining 200 yards down range to the magic 1,000 marker.

    And, I could live with the Z 800 at 7[B].[/B]45x to be sure for 0 to 800+yards. -You know what it's gonna do on 4[B].[/B]5x and 7[B].[/B]45x [B]before[/B] you ever mount the scope! [/SIZE][/FONT][/SIZE][/FONT]

    [FONT=Times New Roman][SIZE=3][FONT=Times New Roman][SIZE=3][FONT=Times New Roman][SIZE=3]With the Z 800, at [B]ANY[/B] set magnification (4[B].[/B]5x - 14x), with the center crosshairs, the bullet will still impact 1[B].[/B]77" high @ 100-yards, and will still be absolute bullseye at 200-yards!
    [FONT=Times New Roman][SIZE=3]But, for a dedicated Long Range benchrest set-up - or if you don't mind having it at 11[B].[/B]8 power all of the time, the Z 1000 bullseyes scratch the 1,000-yard itch.

    [/SIZE][/FONT][I][FONT=Times New Roman][SIZE=3]G-gear
    [/SIZE][/FONT][/I][EMAIL="[email protected]"][B][I][FONT=Times New Roman][SIZE=3][COLOR=#551011][email protected][/COLOR][/SIZE][/FONT][/I][/B][/EMAIL][FONT=Times New Roman][SIZE=3]
    [/SIZE][/FONT][FONT=Times New Roman][SIZE=3][SIZE=5]
    [/B][/SIZE][FONT=Times New Roman,Times New Roman][B]For users who want to know more about how their rifle will perform, a ballistics program (Exbal) from [/B][URL="http://www.perry-systems.com/"][B][COLOR=#551011]http://www.perry-systems.com/[/COLOR][/B][/URL][B] with calculations for all Rapid Z reticles should be purchased. You can explore wind effects; get a profile of trajectory, velocity, energy, time of flight, etc… vs. distance to target. It also has an extensive ballistic reticle function to determine the point blank range data for each of the cross-bars or hashmarks on Rapid Z ballistic reticles for a specified target height.

    [SIZE=3][FONT=Times New Roman][SIZE=3][FONT=Times New Roman][SIZE=3][B]LRB 7x50 laser rangefinder binoculars [/B]
    [/SIZE][/FONT][URL="http://www.newcon-optik.com/lrb7x50.html"][FONT=Times New Roman][SIZE=3][COLOR=#551011][B]http://www.newcon-optik.com/lrb7x50.html[/B][/COLOR][/SIZE][/FONT][/URL]

    [FONT=Times New Roman][SIZE=3]Unbelievable?

    Almost. :)

    [/SIZE][/FONT][URL="http://www.newcon-optik.com/Specs/lrb7x50.pdf"][FONT=Times New Roman][SIZE=3][COLOR=#551011][B]http://www.newcon-optik.com/Specs/lrb7x50.pdf[/B][/COLOR][/SIZE][/FONT][/URL] [/SIZE][/FONT][/SIZE]

    Last edited: Mar 24, 2010