GUN Various AR15 Questions

Discussion in 'On Topic' started by RyeLou, Mar 20, 2005.

  1. RyeLou

    RyeLou OT Supporter

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    I apologize for this in advance. I'm new to them but have a handful of questions and people here seem to be helpful and to the point. I have a few, so answer what you can or what you feel like, thanks in advance.

    What kind of optic is this mounted on the gun, and how does it work (What do you line it up with I guess..?)
    [​IMG]

    And a second pic. for reference (again):
    [​IMG]

    What type of optics are these, and why do people mount them on different parts of their receiver or even the top side of the barrel? I've noticed people move the one above around quite a bit too.
    [​IMG]

    Whats the deal with the 1/9, 1/8 and 1/7 twist thing? I'd imagine that is the amount the bullet spins as it comes out, or has something to do with that. Which is better than? I'd guess 1/9 is the most common.
     
  2. RRTX

    RRTX New Member

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    The optic on the first one is an Eotech, it has a red dot projected on the glass which is used for aiming. It doesn't have to line up with anything, but mounted in the manner which it is it will normally co-witness the front sight post. The second one is an Aimpoint, same basic theory as the Eotech but in a different form. The mounting location is mostly personal preferance, so you will see them mounted at different locations on the rail and with different height mounts. Both were designed mainly for extremely fast target aquisition in CQB situations, but both can be used to aid in longer distance shooting also. The different barrel twists are for stabilizing different weight bullets, but I suck at really explaining that so someone else can take that one.
     
  3. Bigsnake

    Bigsnake OT Supporter

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    The quicker the twist rate (1/7 means 1 complete turn in 7" of barrel) will let you shoot and stabalize a heavier bullet out of the barrel.
     
  4. eWRXshun

    eWRXshun hai

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    1st pic is an eotech.
    2nd pic is a bushnell holosight.
    3rd pic is an aimpoint.
     
  5. footratfunkface

    footratfunkface New Member

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    Exactly. Those first two optics aren't the same thing. The first one is a nice, high end EOTech. The second one is a cheaper HOLOsight. Both accomplish the same basic thing, but the EOTech is a far better quality piece of equipment.

    The Aimpoint and the EOTech exhibit zero parallax, but I do not know about the Bushnell. It's a personal preferrence as to which is better. I myself prefer iron sights over optics, but I'd take the Aimpoint over the EOTech just based on my own personal use of the Aimpoint and the EOTech, and how they look and operate during use.

    People mount their optics in different spots to get different amounts of eye relief, the distance betwixt your eye and the focal lense. Some people prefer a longer relief, some like it shorter. With most red dot type sights, you'll want it out further for a better field of view. It's mostly preferrence, but most people prefer the same amount of relief.

    As for barrel twist rates, it's been explained. The faster the twist rate (1/7 is the fastest on an AR), the longer a bullet you can stabilize. This ends up being a heavier bullet because when you make a bullet larger and heavier for one caliber, you can only increase the length, not the diameter. Longer bullets are less stable in flight without making them spin faster. I now buy only 1/7 twist barrels just so that in the future, I'll be able to shoot heavier bullets than 68 gr. out of my AR. I have a 16" 1/7 M4 profile barrel, and one 16" midlength 1/7 barrel on the way right now.
     
  6. RyeLou

    RyeLou OT Supporter

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    With the A3 flattop model, how easy is it to change configurations with that?
     
  7. GlocksRock

    GlocksRock Glock > You

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    you can get quick release mounts that allow for a repeat zero, so it's extremely easy to quickly change optics with a flattop. larue tactical makes very nice mounts. check them out at www.gandrtactical.com
     
  8. RyeLou

    RyeLou OT Supporter

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    Thanks for the help with these various threads. I've decided to get some car parts (wheels and what not) for my car before I buy a gun, so I'll be getting the rifle later this summer. I thought I was set on a regular A2 sight, but now an A3 with an EOtech sounds pretty damn good..
     
  9. GlocksRock

    GlocksRock Glock > You

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    I :love: my M4gery with the A.R.M.S. #40 BUIS and Eotech 512.
     
  10. phoenixTX

    phoenixTX New Member

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    Of course it depends on what you are going to use the weapon for, but learn to shoot it with the iron sights first ... then add the gadgets.
     
  11. footratfunkface

    footratfunkface New Member

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    Yeah, I generally urge people to learn to use their irons first. If you're good with your irons, you'll be at least quicker if not better with an optic. If you start with an optic and never really learn to use your irons, you won't become as good a shooter, and if the optic fails for any reason, you're screwed.
     

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