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Discussion Starter · #1 ·
I have an AR15 - style rifle with iron sights. I recently started looking to upgrade to some sort of optics, but the choices are bewildering (eg, red dot, laser, ACOG, scope, etc)

Can someone give me a high level description of the major categories of rifle optics and the best uses for each?

Thanks !

steve
 

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  • Iron Sights - pretty straight forward. These are a dual plane sight, a front sight and a rear sight. This requires the shooter to line up their eye, the rear sight, the front sight, and the target. These might be buckhorn sights, peep sights, ghost rings, etc. in the rear, with post, bead, or globe, etc front sights. Stock fitment dictates your eye position over the rifle, and the sights need to line up perfectly, otherwise the shooter has to move to line up their eye to the sights. Due to the front sight size, especially in handguns, iron sights can often offer the least precision of any system, and they do require a bit of time to align if the stock isn't perfectly fit to the shooter. Second to slowest, least or second to least precision.



  • Open Red Dot Sight - These are often called reflex sights, but they could be holographic sights as well. This includes optics like the EoTech lines, Burris Fastfire (pictured above), Trijicon RMR, Leupold Deltapoint, Docter, C-more, JPoint, etc. These have a laser emitter aimed at a reflection pane, once sighted in, these have the advantage that your point of aim drifts very little no matter where your eye is positioned (see gif below) - the shooter no longer has to line up multiple sights or center the aiming point (dot) in the sight window, if the dot is on the target, the weapon is on target. You can see the very slight drift for the aiming point across the plane in the animation below, while the shooter's eye is moving the dot drastically across the sight window. These offer the greatest FOV besides iron sights, meaning the obstruct the least of the shooters view. These two attributes allow very fast target acquisition, compromising some for precision, but allowing for less perfection in stock fitment. Open red dots are FANTASTIC for teaching new shooters, especially kids - put the dot on the target, pull the trigger - that's it. Micro dot styles (trijicon RMR, FastFire, etc) are fantastic for handguns, due to their compact size and low weight, coupled with their fast target acquisition. One disadvantage, however, is that in high light, the open dot can get washed out by background light, so the shooter can lose the aiming dot. These often utilize 2-8MOA, sometimes larger aiming points. Highest speed, least or second to least precision.





  • Tubular Red Dot - these operate on the same principle as the open type red dot above, but are constructed with a tubular housing. This tubular housing obstructs more of the shooters field of view, but it helps the shooter to better center the dot for more precise shot placement. These also tend to have better low light performance than open red dots - especially with a fine dot reticle - because again, open red dot aiming dots can get swallowed in high brightness. Oppositely, the shooter can get back-blinded more easily in tube type red dots if the reticle is too bright compared to the surrounding field. These are good on target pistols and on hunting type rifles where pure speed isn't as critical and improved precision IS critical. Typically these offer 2-8MOA dots. Middle ground for speed, middle ground for precision.


  • Telescopic Sight - everybody is familiar with a "scope". These incorporate magnifying lenses with an internally mounted or glass etched reticle. Typically, the "crosshairs" or center aiming point of a reticle is 1/4MOA, so this offers the highest degree of precision - and coupling that with magnification allows the shooter to place their shot on target even more precisely still. The downside is that the shooter must align their eye with the erector tube, because unlike the red dot sights, the crosshairs will not chase the target as your eye moves around - even if the crosshairs are on target, if the shooters eye isn't aligned properly to the scope, the weapon may not actually be on target. Example of this below - note that the laser boresighter red dot at the lower left of the target doesn't move - the firearm doesn't move - but the crosshairs are drifting 1/2-3/4" in any direction, at 10yrds. Since they offer the highest degree of vision obstruction as well as the highest degree of precision, telescopic sights are best utilized for mid to long range shooting, especially for hunting. Slowest system, but highest precision.




  • ACOG - Technically, this is a glass etched telescopic sight, with a phosphor illuminated reticle. Some also have fiber optic light capture capability, or LED illumination as well. The illuminated reticles and simple design of ACOG sights, with large scale reticles allow fast sight acquisition, but with improved precision of a telescoping sight. These are typically reserved for short to mid-range shooting where gross aiming is critical for fast acquisition, but a bit more precision is necessary. These tend to be a little faster on target acquisition, and a little less precise than a scope. Middle ground speed, middle ground to top end precision.

  • Laser "sights" - These really aren't "sights" in themselves, but rather a projected aiming point applied to the target. They're a mounted option - not usually in the same position on top of the receiver, that emits a laser onto the target itself. These are very easily washed out in daylight, can be hard to see on target at long ranges, usually expand in size over range - decreasing precision - and overall, they don't have a lot of utility (but they sure look cool in the movies). For defensive shooting, farsighted shoots CAN benefit from lasers, as they'll be able to focus on the dot on the target and focus the target itself, but may not be able to focus their eyes on their sights. There are axial disparity issues with lasers as well - the line of the bore is not in line with the axial center of the laser, so you essentially have an elongated "X" where one leg is the bullet's trajectory and the other leg is the laser line. At longer ranges, that disparity reveals itself (and again, the laser disappears). Depending upon training, laser pointers can be faster or slower than red dot sights. They allow heads up shooting from any position, but the precision is really poor. They really only offer an advantage in low light, close range defensive shooting, and that's only if you're willing to give up all of your conventional firearms training and become reliant on the laser.
 

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Believe it or not, if you can tell us how you plan to shoot: off hand, prone, from a bench, with a bipod, at what distances and what you plan to shoot at, we could narrow down your options considerably.

For example, I am mostly a target shooter, shooting from a bench either with a benchrest setup or a bipod. For those uses, I buy mostly high powered target scopes, with 36X being my standard. When I head out with my varmint rifles, I mount mid level variable magnification scopes usually in in the 6-18X variable range.

Because I am always shooting at tiny targets, I have no use for a red dot scope. You do not find red dot scopes with 1/8 MOA accuracy. If I was shooting at a deer somewhere under 200 yards, l would not need greater than 6X. Even a decent red dot scope would be fine then.

There are many other variables affecting the choice to be made in optics. A very important one is your budget for optics.
 

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Discussion Starter · #6 ·
Varminterror and others,

Thanks for the outstanding tutorials. These help a lot!

I'm not really sure yet of the primary use of my AR-15. I like shooting at the range at all different distances, but I am not a good shot at this point so use large and/or close targets. Want AR-15 to work also as home defense or Zombie apocalypse.

It sounds as if there are a number of good solutions for different weapon applications. For my first optic I'm thinking about getting an Aimpoint PRO for the home defense angle and for short targets.

Thanks again everyone - I'm going to show this thread to some friends of mine with similar questions.

Steve
 

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Outstanding posts, especially VT's. That took a lot of work on his part, but a lot of newbies on our forum will benefit from it. Thank-you, VT.

One thing that I would like to add is the experience factor. It does take time and experience, working with each type of sight setup to develop proficiency. I do notice a tendency with some new shooters to give up on one sighting system or another a bit too quick, at times, moving on to something else in the hopes of finding a quick fix.

There's also a great deal of personal preference, involved, so by all means ask questions and explore the options, but don't be in a hurry to form opinions untill you have a chance to work all of them. No substitute for shooting experience.
 

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Aimpoint Pro is a good first choice. 2 MOA dot will give you reasonable accuracy but it isn't designed for precision shooting.

It is a very effective optic for close quarters fast moving shots, but effective on man sized targets out to 300 meters.

As you determine what purpose you want the AR to fill, you'll be able to narrow down the optics choices. I have a 1-6X on my AR, which gives me the fast both eyes open ability of a red dot, albeit not as good, with the 6x top end for longer shots.

Look for the best quality glass you can afford like you did with the Aimpoint. Many will try to increase magnification to make up for the quality of the glass but then hit problems with lack of contrast, low light performance and eyes getting tired looking through poor quality optics.
 

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The aircraft shown appears to be a Me262 - the world's first operational jet fighter. I can barely ID the iron cross on the back of the fuselage.

Burris goes for high impact advertisements.

A .50 BMG equipped with such a sight (then) would be very effective.

Good job VT - lots of work on that one.
 
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