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The AK uses a different caliber, and the BDC will not work with it.

I don't think the ACOG vs Eotech in accuracy is a valid consideration. Both are extremely accurate but serve somewhat different purposes. The Eotech Holo Sights are made for Close Quarters Combat, have no magnification (unless you add the Eotech or similar magnifier), and are made for extremely fast target acquisition.

The ACOG on the other hand is a magnified optic (I've seen them anywhere from 1.5x up to 4x or so) and as such are made for taking shots at further distances. You'll see the higher dollar ACOGs complete with a small red dot sight on top. This allows for extremely fast target acquistion in Close Quarters Combat as well as accuracy with longer shots.

I haven't read too much on the COMP M4's from AIMPOINT, as that's honestly not on my short list (I'm deciding between an ACOG and Eotech myself). As such, I can't comment on the Comp M4 and similar.

I think it's honestly going to come down to what you want to use your SBR for. If you want to take closer shots with good accuracy, steer toward the Eotech. If you want to take longer shots, lean toward the ACOG. When you add the magnifier to the Eotech, the money saving for the Eotech over the ACOG is negated. I'm leaning toward the ACOG as of now because I like being able to take a bit longer shot.

Hope I've answered your question satisfactorily.
 

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ONE MAJOR THING YOU'VE FAILED TO CONSIDER IS THE WEAPONS EFFECTIVE RANGE VERSUS THE EFFECTIVE RANGE OF THE OPTIC....BOTH OF YOU ACTUALLY

For an SBR, an ACOG IMO is not the best choice and certainly not the best choice for the money...that optic is better intended for a longer barreled rifle 16"+.....first of all i say this because the optic will well outperform the accuracy of a 10" barrel....the maximum effective range of an SBR will be about 100-200 yards MAX....IMO the sig 556P will not shoot accurately at 200....maybe a Noveske shorty with stainless barrel....anyways, an ACOG far surpasses that and therefore assinine on an SBR....

i would and i may get an EOTECH XPS....but i am still leaning more toward an aimpoint...

The best options for an SBR for me would be:
  • Aimpoint Micro T1 or H1
    Aimpoint Comp Series (M2 would be all thats needed)
    EOTECH 511.A65
    EOTECH XPS2
 

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556OPER8R said:
For an SBR, an ACOG IMO is not the best choice and certainly not the best choice for the money...that optic is better intended for a longer barreled rifle 16"+.....
Guess I should have clarified. I own a full-size 556ER.

I failed to take into account the SBR factor in recommending the ACOG. Thanks for clarifying that.
 

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alfred10 said:
Will the bullet drop dots work with the Sig 556 SBR? Will this site also work with an AK? Not sure what sight to get. I love the battery life of the Aimpoint but cant see getting a small dot that has less MOA accuracy than the Eotech with the large dot. How much more accuret is an ACOG than an Eotech?
...BDC reticles are calibrated using a specific cartrage fired out of a specified barrel length at a specific density altitude...usually sea level or 1000 feet AMSL...

...generally...but no always... in .224 caliber this usually means a 14.5 inch barrel using M855 ammunition... there are exceptions...for example...some Acogs are calibrated using M193 ammunition fried out of a 20 inch barrel...

...the BDC reticles are calibrated to compensate for the acceleration of gravity...the degree of bullet drop will depend on it's duration of flight until it strikes the target..."some" important considerations are the muzzle velosity developed in a a particular length barrel...the projectiles ballistic coefficient and the air density...

...mabey this tread will give you some idea idea...i suggest you do some reading in the optics section regarding this and the choice of optics

... http://www.sigarms556.com/viewtopic.php?t=8955

...to answer your question...no...the BDC features of the Eotech will not work for your SBR using the ammunition it is calibrated for...due primarily to the difference in muzzle velosity between a 10 barrel and a 14.5 inch barrel...

...i would recomend an Aimpoint...in particular a Comp M4...or a low power variable scope for your SBR...
 

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Discussion Starter #6
I am suppose after reviewing range factor, I should be looking for an Eotech that could work on an AK, M4, Sig 556, and M1A. I really like the 557.AR223 . How many yards will the aiming dots work on the Sig SBR? Would the Dots line up since there are three and it is made for an M4?

http://www.eotech-inc.com/product.php?id=8&cat=1

Will this kit work with the magnifier work with an SBR sig 556?

http://www.gotogazzos.com/catalog/produ ... &pid=70703

Who makes the best quick detach mount that will work with an AK 47, Sig 556 SBR NFA 10inch, and Colt m4? I want a durable mount that is easy to re-zero. Who makes the best co witness back up iron sights for the sig?

My beef with the Aimpoint is that they are 4MOA at 100 yards with a smaller dot. The Eotech is 1MOA. Not sure why a larger circle that is quicker would be more accuret than a smaller one? If the Aimpoint micro was 1moa I would grab it.
 

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If your looking for an Eotech for your SBR, don't get one of the variants that has the multiple aiming dots. They won't be accurate due to the lower muzzle velocity from the 10" barrel, and will just be visual clutter that can be distracting.

First thing you need to decide is if you will be using a magnifier with your Eotech. It's a bit overkill on an SBR considering the lower effective range, but I've got one I use for zeroing and greater accuracy at longer distances. The majority of the time I've just got it flipped to the side or removed. Follow up shots are much easier and faster without magnification. If you decide to get a magnifier, get the G23 FTS, and choose an Eotech with the buttons on the side rather than the back so you can adjust the brightness when using a magnifier.
http://www.opticsplanet.net/eotech-gen- ... 3-fts.html

Then it's a matter of choosing which model Eotech you want. The main points to consider are the type of battery you want to use, and whether or not you will need night vision mode (if you have a set of night vision goggles). Also, the newer models with the side buttons are 7mm taller than older ones.

I wanted an Eotech that has it's buttons on the side, uses CR123 batteries, and has night vision mode. Coincidentally enough, it turned out to be an Eotech model 556 :)

Also, GG&G makes flip up lens covers for all models of Eotech now (not just the older ones), and are a really nice addition.
http://www.operationparts.com/SearchRes ... Search.y=9
 

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556OPER8R said:
ONE MAJOR THING YOU'VE FAILED TO CONSIDER IS THE WEAPONS EFFECTIVE RANGE VERSUS THE EFFECTIVE RANGE OF THE OPTIC....BOTH OF YOU ACTUALLY

For an SBR, an ACOG IMO is not the best choice and certainly not the best choice for the money...that optic is better intended for a longer barreled rifle 16"+.....first of all i say this because the optic will well outperform the accuracy of a 10" barrel....the maximum effective range of an SBR will be about 100-200 yards MAX....IMO the sig 556P will not shoot accurately at 200....maybe a Noveske shorty with stainless barrel....anyways, an ACOG far surpasses that and therefore assinine on an SBR....
...none of this makes any sense to me... "maximum effective range" is meaningless unless put into some kind of context...and optics do not have "effective ranges"...

...using shorter barrels decreases the velosity potential of a cartrage...and does not necessarily reduce accuracy...in fact...short barrels sometimes enhance accuracy at the expense of developing greater velosities due to being less prone to flexing and barrel whip among others...all other things being equal...

...the maxium effective range on point and area targets is far greater with the P556 SBR than you would think...especially when using the longer...more ballistically efficient projectiles...although the 556 carbine does have an advantage due to the greater velosity developed....it would not be unreasonable to expect a good marksman to achieve accurate hits out to well past 400 yards...stating that " the maximum effective range of an SBR will be about 100-200 yards MAX."... and that a P556 SBR will not shoot accurately to 200 yards is just plain not true...
 

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I would agree with Ullie -- the Aimpoint M4 would be a very good choice for an SBR and an AK, and with the right mount (LaRue Tactical comes to mind) would transfer between weapons readily.

Main reasons why - as with any optic, it is all in the specs:

• 2 MOA dot for close quarters combat and long distance engagement
• Matches perfectly with Aimpoint 3X Magnifier (easily add this later)
• Internal voltage regulator and Super ACET technology allows up to 80,000 hours (over 8 years) :shock: of daytime operation on one AA battery :shock:
• Seven night vision compatible settings and 9 daylight settings
• Front lens opening threaded for addition of killFlash® anti-reflective device
• Submersible to 150 feet
• Standardized as the US Army’s new M68CCO
 

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Discussion Starter #10
Whats the accuracy difference at 100 yards between the Aimpoint Comp M4 and Eotech? I thought the Eotech was more accuret than the aimpoint? Will the Aimpoint and regular eotech with a single dot shoot point of aim? Does aimpoint make a flip down magnifier?
 

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ullie said:
556OPER8R said:
ONE MAJOR THING YOU'VE FAILED TO CONSIDER IS THE WEAPONS EFFECTIVE RANGE VERSUS THE EFFECTIVE RANGE OF THE OPTIC....BOTH OF YOU ACTUALLY

For an SBR, an ACOG IMO is not the best choice and certainly not the best choice for the money...that optic is better intended for a longer barreled rifle 16"+.....first of all i say this because the optic will well outperform the accuracy of a 10" barrel....the maximum effective range of an SBR will be about 100-200 yards MAX....IMO the sig 556P will not shoot accurately at 200....maybe a Noveske shorty with stainless barrel....anyways, an ACOG far surpasses that and therefore assinine on an SBR....
...none of this makes any sense to me... "maximum effective range" is meaningless unless put into some kind of context...and optics do not have "effective ranges"...

...using shorter barrels decreases the velosity potential of a cartrage...and does not necessarily reduce accuracy...in fact...short barrels sometimes enhance accuracy at the expense of developing greater velosities due to being less prone to flexing and barrel whip among others...all other things being equal...

...the maxium effective range on point and area targets is far greater with the P556 SBR than you would think...especially when using the longer...more ballistically efficient projectiles...although the 556 carbine does have an advantage due to the greater velosity developed....it would not be unreasonable to expect a good marksman to achieve accurate hits out to well past 400 yards...stating that " the maximum effective range of an SBR will be about 100-200 yards MAX."... and that a P556 SBR will not shoot accurately to 200 yards is just plain not true...

Couple points, some in agreement with you and some less so...

One could argue that "certain" optics to have a max effective range due to the fact that a red dot with a 4moa dot is covering a 16" circle on a target at 400, which isn't terrible, certainty accurate enough to achieve torso shots on a person at that range, which is good enough for most of the military, but there are a lot of uses for which the effective range of such an optic would be limited to closer range, perhaps 200 or even 100 yards depending on what you're doing with it.

But yea, I'm just being a smart ass, there isn't anything really stopping someone from practicing and learning to shoot farther accurately with a 4moa dot, but it just isn't all that practical.

About barrel length, I have heard that the first 3" of barrel are what determines accuracy (although flaws in the muzzle can ruin it), and I have also heard what ullie said about shorter barrels being stiffer and sometimes more accurate out to a certain range.


To the OP:


If you want to figure out what your true effective range is, its going to be determined by lethality more than accuracy, since 223 will stay on target far after it has lost lethal energy. So just look up what they say the minimum velocity for fragmentation is in 223 for whatever grain bullet you're using, and figure out how fast its coming out of your muzzle, and then you can figure out how long it takes for its speed to drop down to the minimum for lethality.

Its a lot of math and i hate math so im not going to help you, but the formulas are all out there, just google em.
 

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alfred10 said:
Whats the accuracy difference at 100 yards between the Aimpoint Comp M4 and Eotech? I thought the Eotech was more accuret than the aimpoint? Will the Aimpoint and regular eotech with a single dot shoot point of aim?
I think you're missing something here. A rifle can have a measured accuracy with a specific round. A person can be said to have a certain accuracy to their shooting. An optic doesn't have any accuracy itself, as it has nothing to do with the physics of how a bullet reaches the target.

Accuracy is commonly measured in Minutes of Angle (MOA), which is aprox 1" at 100 yards. If an optic has a 1 MOA aiming dot, the dot will cover an area 1" wide at 100 yards, a 2" area at 200 yards etc. If it has a 4 MOA dot, the dot will cover an area 4" wide at 100 yards, 8" area at 200 yards, etc. This does not denote accuracy though, it is simply the size of the aiming dot.

Now many shooters may find that they shoot more accurately with a 1 MOA dot that a 4 MOA dot, because it's easier to put the target directly behind the smaller dot than trying to center it behind a larger dot. However, everything else being the same, with a rifle zeroed at the distance being shot, your rounds will place directly behind the center of the aiming dot, regardless of it's size.

There are also many shooters that find it more difficult to rapidly acquire targets with a 1 MOA dot than a 4 MOA dot, because of it's smaller size, and the eye/mind having to work a little harder to build the sight picture. Eotech has compensated for this by providing a 65 MOA circle around the center aiming dot, allowing for faster target acquisition with a smaller dot. Again though, this has nothing to do with 'accuracy' of the optic, but rather how easy it is for the shooter to rapidly acquire a sight picture.

A loose definition of accuracy can be defined as the expected size of a group at a given distance. Note that accuracy is non-linear with distance. If a rifle can shoot 1" groups at 100 yards, that doesn't indicate that it will shoot 5" groups at 500 yards. The reason is that as a bullet decelerates, especially at the point where it goes sub-sonic, and as it's rotation slows, the size of the group will open up. A rifle that shoots 1" groups at 100 yards may shoot 7" groups at 500 yards, etc.

Another thing I think you are missing is that an optic is zeroed for a given distance. You can think of it this way - the bullets starts out low, and travels upward, crossing your point of aim at your zero distance, then continues traveling upward in an arc until it starts to fall, then crosses through your point of aim again, and then continues falling until it hits the ground. In reality the bullet doesn't actually travel upwards (it's always falling from the moment it leaves the barrel), whats happening is that the optic is looking at a downward angle through the bullet path, but it's easier to comprehend if you think of the bullet shooting at an upward angle.

Generally, you want to select a zero distance that will provide the least amount of vertical variation at the ranges you expect to shoot. Generally, with a 5.56/223 round that distance is 50 yards, and you should never be more than +/-2.5" out to several hundred yards.

If you absolutely need point of aim to equal point of impact for a given distance, you can get a ballistic calculator that factors in the the muzzle velocity of a given round from a given rifle, the bullet weight, ballistics coefficient, air density, temperature, humidity, the height of the sight above the bore, wind speed and direction, rotation of the earth, etc, and can calculate how many clicks you need to adjust your optic from where it's zeroed.

There's a lot of info out there that you should make yourself familiar with. You don't need to become an expert, but should understand the basics before jumping into spending several thousand dollars on a building an SBR.
 

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I have a trijicon tripower on mine and couldn't be happier with it. I've become accustomed to and appreciate the chevron.

I like having the folding stock option on my SBR so I wanted to keep the upgoing factory charging handle. This ruled out an eotech for me for my sbr.

Just my 2 cents.
 

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...alfred10

...everything in an optic is a compromise...generally...when you gain something in one area you'll loose something in another...especially when moving from one type to another...

...IMO..the best advice you could follow now is to be patient...and do some homework to get a better understanding of how an optic works and learn the differences between each class of optic..such as a reflex / holographic sight versus a low power variable scope...high power scope...the reticle types and their differences in function and so on...the advantages and limitations inherant to each class...

...then i suggest you base your optic choice based on "your" intended primary use...there are an almost infinate number of optics to choose from...some good...some not so good...and price isn't always an indication of quality or function...
 

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alfred10 said:
...why would you use a fixed power optic with extreamely short eye relief as a combat sight...or otherwise...

...IMO...both are very poor choices for any application...

...i would use a reflex or holographic sight on your SBR "without" a magnifier...i suggest an Aimpoint Comp M4...if you want magnification i would go with a low power variable scope...this Nightforce with the FC-2 reticle...

http://nightforceoptics.com/nightforces ... 24nxs.html

...or a Leupold...

http://swfa.com/Leupold-15-5x20-Mark-4- ... 45043.aspx
 

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alfred10 said:
I have both of those and like shooting with them a lot. I prefer the illuminated chevron to the non illuminated crosshair and while shooting with both eyes open it is very similar to a red dot.

As far as the eye relief goes, Ullie is once again correct, they are very limited on eye relief, as soon as you move your eye away from the ACOG the field of view diminishes significantly, I just keep my eye close and my stock collapsed, if you aren't comfortable being right up close to the sight, then these aren't for you.
 
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