How the heck does a red dot scope work?

Discussion in 'General Gun Discussions' started by jamz, Jun 29, 2004.

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  1. RJ357

    RJ357 Member

    Jun 9, 2004
    Jim -
    That is basically correct. A virtual image, however, can exist at any position. The reticle or red dot is a virtual image. It has all the characteristics of a real image, like parallax and focus. If you focus your eyes on the distant target, the red dot or reticle will also be in focus, even though the physical reticle or dot is very close.
    Better scopes have a parallax adjustment which can place the effective position of the crosshairs anywhere from a few tens of yards out to infinity.
    When no adjustment is present, the parallax free distance is set by the manufacturer; usually 100 yds for a rifle scope and 50 for pistol. I believe different parallax free distances are available for some scopes special order.
    An interesting thing about this is that the reticle or dot can actually be behind the target!
    Looking at a 200 yd target through a typical scope, the reticle is in front of the target (at 100 yds). Parallax is as you might expect for two objects at 100 and 200 yds respectively. If you move your head to the right, the reticle will shift to the left relative to the target.
    If you look at a target at 50 yds, the reticle is still at 100 yds. And the parallax is again as you might expect for objects in this configuration. Moving your head to the right will cause the reticle to also shift to the right.
    This is easier to understand if you imagine that the target is transparent and can be placed either in front of or behind the reticle.
    In spite of it's physical location, the reticle behaves as if it were at 100 yds.
  2. jamz

    jamz Member

    Nov 28, 2003
    Seacoast NH
    So how do I mount one on my Garand? Do I weld something on the barrell?

    -jamz ducks ;) :p
  3. chevrofreak

    chevrofreak Member

    Jan 5, 2003
    Billings, Montana
    I read somewhere that most dots are projected at what we percieve is 25 feet (this was checked with a range finder on a camera) so that we dont have something that seems right up in our face when we are trying to focus on the target.

    I have a red dot on my AK, one on my MKII and I had one on my shotgun. I love these little buggers, even though I'm too cheap to buy an expensive one.
  4. AgentOrange

    AgentOrange Member

    Aug 3, 2007
    i have a nikon monarch on my AR...

    one thing to remeber to when you buying a red dot site is the MOA size of the dot. some are low ( 1 to 2 inches at 100 yards) and some go up as high as 10 ( 10 INCHES AT 100 YARDS.)

    my monarch is adjustable from 1 to 10 MOA at 100 yards.

    also, remeber that when your lining your red dot up to do it as close to the longest distance youll be shooting as possible. if you line it up say at 25 yards, when you move back to say 50 yards it WILL be way off. also, its best to get a variable MOA dot size rig, like mine, and zero it at the smallest dot size you have. that way, youll be in the mix if you decide to get yourself a magnifier at a later date. if you have a 1MOA dot size and a magnifier, you can shoot some pretty tight ass groups without an issue. i always line mine up at the 1MOA dot and then depending on how far i am out, or if im wanting to do some precision shooting i can turn the dot size down and i know im on the money.

    ( i know this is a old thread but had to throw my 2 cents into the mix)
  5. TexasRifleman

    TexasRifleman Moderator Emeritus

    Feb 16, 2003
    Ft. Worth

    MT GUNNY Member

    Aug 19, 2006
    Kalispell MT
    Imagine a scope without a reticle or dot. now install a lazer. when you look through the scope you see your lazer designation on the target. That is essentially what the red dot system is producing, and why it looks like the dot moves.
  7. dmazur

    dmazur Member

    Apr 28, 2007
    Pacific NW
    Here's a Garand with a scout mount and an great.


    This type of mount replaces the rear handguard. Large channel down the center permits use of original iron sights if you just remove the red dot or LER scope. It is clamped on with an amazing number of screws -- no welding.

    If you ever get tired of it, it is easy to remove it and replace the original handguard.
  8. gym

    gym member

    Dec 9, 2007
    Ok I started to get the hang of this, now is the ACOG, different? or similar?
  9. waldonbuddy

    waldonbuddy member

    Jan 29, 2009
    How about this Bushnell.....which is supposed to be an Acog knockoff.....

    Ive got one, yet-to-be-zeroed. Anyone using these. I have mounted it on my rifle and its level, and bright.
  10. Trebor

    Trebor Member

    Feb 15, 2003
    This thread is five years old, btw.
  11. jojo200517

    jojo200517 Member

    Mar 22, 2009
    NECRO from hell. Also people seriously learn to spell, its laser, Light Amplification by Stimulated Emission of Radiation. Repeat after me THERE IS NO Z.

    As for red dots, I have had mine on the AK and on the shotgun. For now it just collects dust. It just seemed to clunky and big to me I always banged it on something. I can't see putting an ACOG on a gun when it costs many times the price of the gun.
  12. Dulvarian

    Dulvarian Member

    Mar 5, 2009
    South Carolina
    Thread necro or not, I want to put an ACOG on my SIG 556. Right now, it just has an Eotech. And yes, I shoot about a 1" group at 100 yards with decent ammo. Less than that with good ammo.

    Lol, that's some serious necro ability there, AgentOrange.
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