GUN AR-15 crew get in here...

Discussion in 'On Topic' started by Accord, Feb 1, 2006.

  1. Accord

    Accord New Member

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    I have a Bushmaster 20" A3 and want to set a completely zero my rifle from scratch.

    According to the USMC Rifle Marksmanship Manual, the rear sight elevation knob should be first bottomed out when initially zeroing your rifle and when bottomed out should be 3 clicks counterclockwise from the 6/3 marking. It then says if it's not 3 clicks counterclockwise from 6/3 when the base is bottomed out, it needs to be adjusted by a qualified armorer. Then you need to rotate clockwise until 6/3 is aligned with the index mark.

    Here is a picture I just took of my rear sight base completely bottomed out, and as you can see, it's not aligned properly like the USMC Rifle Marksmanship Manual states it should be:

    [​IMG]

    What should I do? Where should my elevation knob be set for what i'm trying to do? The Rifle Marksmanship Manual is specifically for an A2 and I have an A3 so i'm not sure if that makes any difference.

    I did read that some Bushmasters have out of spec rear sights/carry handles that are problematic, do I have one of those?

    Thanks a lot
     
  2. USMCsilver

    USMCsilver Active Member

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    I don't remember doing the "three clicks" thing. I have my old range book somewhere, but that doesn't sound right. I thought we kept it on 6/3 and then -- wait -- "6"? IIRC, ours were marked "8/3". Odd...

    I dunno dude. The A2/A3 thing should make no difference. However, if the rear carry handle unit is to somewhat of a different spec, then the 6 and 8 thing would make sense. Good luck.
     
  3. Dsking85

    Dsking85 New Member

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    that's just USMC standards. i usually set my absolute zero at 1 click up from bottomed out, or that's how we do it on my rifle team, and then we make an index mark w/ white paint pen. so it doesn't really matter. i doubt you'll use all your elevation anyway.
     
  4. silversilvia

    silversilvia OT Supporter

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    My A2 says 8/3 as well.
     
  5. Accord

    Accord New Member

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    Yeah... for some reason A2's have 8/3 but A3's have 6/3. Not sure why there is a difference in the number but it says to just assume they're the same.

    When you did an initial zero on your rifle after picking it up from the armory or something, did you bottom out the rear sight base or actually put it directly on 8/3 (6/3 in my case)?
     
  6. Y2kAccord

    Y2kAccord Everything happens for reasons I just dont know

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    Using this to learn mine.. last time I was shooting High and to the right, but in 1/4" groups.. havent got to shoot anymore, I guess I will try some adjusting when I hit the range again
     
  7. A96HondaAccordCoupeEX

    A96HondaAccordCoupeEX Silver Member

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  8. Accord

    Accord New Member

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  9. Y2kAccord

    Y2kAccord Everything happens for reasons I just dont know

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  10. footratfunkface

    footratfunkface New Member

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    I killed a guy with a trident.
     
  11. jimmybuffett

    jimmybuffett New Member

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    I SAW THAT.....maybe you should find a safe house and lay low for a while...
     
  12. USMCsilver

    USMCsilver Active Member

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    Honestly, that was quite some time ago, but IIRC, it was put on the 8/3 and zerod from there. I believe that 8/3 was the benchmark and was to control all elevation and the front sight was actually raised to accomodate a zero at the 300 yard mark, but only after adjusting it to where it needed to be after achieving a BZO at 30 meters (or was it 25?).

    So, set it at 8/3, tape off 30 meters (25 maybe) and sight in your rifle. Adjust the front sight post elevation to achieve your vertical element. Then, when you go to shoot at different distances, never touch your FSP again, use the elevation adjustment on the rear sight.
     
  13. jimmybuffett

    jimmybuffett New Member

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    i believe my bushy manual says 25 meters
     
  14. Accord

    Accord New Member

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    Thanks for the info, i'll be going to the range tomorrow to try this out.
     
  15. mongorunner

    mongorunner New Member

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    howd i know you were going to make referances to the Corp:hsugh:
     
  16. 7

    7 First comes smiles, then lies. Last is gunfire.

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    Way to keep your head on a swivel
     
  17. USMCsilver

    USMCsilver Active Member

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    Was that pointed towards me or Accord?
     
  18. Furner

    Furner New Member

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    that link has some good shit, you all keep it bookmarked.
     
  19. Accord

    Accord New Member

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    So let me get this straight...

    If I have a zero set on my rifle that is PERFECT at 100 yards and i'm going to be firing at 200 yards, I would increase the elevation knob by 1 click and each click represents an additional 100 yards?

    So if I had a zero that was good for 100 yards and wanted to set it for 200 yards, i'd bump the elevation knob up 1 clicks?
     
    Last edited: Feb 1, 2006
  20. Dsking85

    Dsking85 New Member

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    no. it depends what kind of adjustment you have on yours. probably 1/2 MOA. if you need to move it up 5 inches, you do 10 clicks up. for my match rifle, my 100 yard zero is 8 up from MZ, and my 600 yard is 43 up
     
  21. Accord

    Accord New Member

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    I have no idea... I just have a regular good old 20" A3.
     
  22. Dsking85

    Dsking85 New Member

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    well, my match rifle has 1/2 or 1/4 MOA, i can't remember, so if you need to move it up 4 inches at 100 yards, you multiply that by either 2 or 4, and move it up that much.
     
  23. A96HondaAccordCoupeEX

    A96HondaAccordCoupeEX Silver Member

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    I zero my rifles at 50 yards. That gives me a flat enough trajectory out to 250 yards.
     
  24. Accord

    Accord New Member

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    nono, i'm not talking about minor adjustments at a certain range....

    I mean if I already have a perfect zero at a specific range such as 100 yards and want to make the same zero good for 200 yards, is that just 1 click of the rear elevation knob to take it from 100 to 200 yards?
     
  25. Accord

    Accord New Member

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    The USMC 300 meter battlesight zero is supposed to be zeroed at 36 yards, with this zero, will I have a flat enough trajectory for anywhere from 100 yards out to 300 yards without having to make any elevation adjustments or?

    I wish my range wasn't 45 minutes away :o
     

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