Here is a quick guide i found helpful from the 68forums.com.
INTRO:
I have put together this thread as an informative thread for the new guys or anyone else who needs help with selecting the appropriate Optic for his/her 6.8SPC. I am not here to tell you what Optic you should use. Instead, I will provide the Pro's and Con's of different types of Optics and let you decide for yourself. Before you decide which optic you want, you really need to decide what type of optic (Red dot, ACOG, variable, or fixed), is best for you.
OPTIC TYPES:
I. Combat Oriented Sights. (Speed).
A. Red Dots. Range: 0-300 Yards. Ideal Range: 0-100 Yards.
1. Uses:
a. One of the best CQB (Close Quarters) sight available due to rapid target acquisition.
b. Good all purpose Military/Law Enforcement sight. Limited only by 1X magnification.
c. Excellent for hunting where speed is desired over magnification.
2. Pro’s:
a. Generally very rugged.
b. Unlimited eye relief.
c. Parallax Free.
3. Con’s:
a. Uses batteries. (Although some have a battery life of 50,000 hrs.).
b. 1X magnification. (Although a 3x or 4x magnifier can be used for added magnification.).
c. Can fail.
4. Examples:
a. Aimpoint Scopes.
b. EOTech Holosights.
c. Trijicon Tri-Power.
d. Trijicon Reflex.
B. Micro Red Dots. Range: 0-300 Yards. Ideal Range: 0-100 Yards.
1. Uses:
a. Best when piggy backed on a scope such as an ACOG or Variable-Power Scope for close range work or as a Back-up sight.
2. Pro’s:
a. Light weight.
b. Unlimited eye relief.
c. Parallax Free.
3. Con’s:
a. Uses batteries. (Although the Aimpoint Micro has a battery life of 50,000 hrs.).
b. 1X magnification.
c. Can fail.
d. Generally not very rugged.
4. Examples:
a. Aimpoint Micro.
b. JPoint.
c. Docter.
d. Burris Fast-Fire.
C. ACOGs. Range: 25-600 Yards. Ideal Range: 25-400 Yards.
1. Uses:
a. Good CQB scope with enough practice. Best when used in open areas where magnification can be used.
b. Best all purpose Military scope.
c. Excellent for hunting where speed and magnification is desired.
2. Pro’s:
a. Generally very rugged.
b. No batteries.
c. Fixed magnification for simplicity. (ACOGs: 3.5X35, 4X32, 5.5X50).
d. BDC Reticle if you are ammo matches the trajectory of the reticle.
e. B.A.C. concept on some ACOG's.
3. Con’s:
a. B.A.C. requires practice.
b. Short Eye Relief.
c. Not parallax Free.
d. BDC Reticle if you are ammo does not match the trajectory of the reticle.
II. Precision Scopes: (Accuracy).
A. Fixed-Power Scopes. Range: 50-600+ Yards, depending on magnification.
1. Uses:
a. Excellent sniper/hunting/target shooting scope when simplicity is desired over variable magnification.
2. Pro’s:
a. Fixed magnification for simplicity.
b. Generally very rugged.
c. Batteries not an issue since reticle is black.
3. Con’s:
a. Not parallax Free.
b. Eye relief is critical.
c. Magnification hinders short range use. (Although a Micro Red Dot can be piggy backed for short range.).
4. Examples:
a. IOR 6X30 Tactical Illuminated 35mm Rifle Scope.
b. IOR 4X24 Tactical Illuminated 30mm Rifle Scope.
c. Leupold 10X40 Mark 4 LR/T 30mm Rifle Scope.
d. Super Sniper 10x, 16x, and 20x.
B. Low-Power Variable Scopes. Range: 0-600 Yards. Ideal Range: 0-400 Yards.
1. Uses:
a. Good CQB scope.
b. Good all purpose Military/Law Enforcement scope.
c. Good for hunting where speed and magnification is desired.
2. Pro’s:
a, Variable magnification offers options. (1-4X magnification.).
b. Batteries not an issue since reticle is black.
c. Best ones have either a BDC Reticle or a BDC Type Turrets.
3. Con’s:
a. Not parallax Free.
b. Eye relief is critical.
c. Generally not very rugged.
d. Not as fast in CQB as Red Dots.
4. Examples:
a. Schmidt & Bender 1.1-4X20 Illuminated CQB Short Dot 30mm Rifle Scope.
b. Horus Vision Model 1000 1-4X24 Illuminated 30mm Rifle Scope.
c. IOR 1.1-4X26 CRT Illuminated 30mm Rifle Scope.
d. Leupold Mark 4 1.5x5-20 Illuminated 30mm Rifle Scope.
e. Swarovski Z6i 1x6 illuminated circle dot reticle.
C. Medium-Power Variable Scopes. Range: 50-600+ Yards, depending on magnification.
1. Uses:
a. Excellent sniper/hunting/target shooting scope when variable magnification is desired.
2. Pro’s:
a. Variable magnification offers options.
b. Optical glass makes identification easier.
c. Batteries not an issue since reticle is black.
d. BDC Reticle or a BDC Type Turrets.
3. Con’s:
a. Not parallax Free.
b. Eye relief is critical.
c. Magnification hinders short range use. (Although a Micro Red Dot can be piggy backed for short range.).
4. Examples:
a. Schmidt & Bender 4-16X50 Police Marksman II 34mm Rifle Scope.
b. Horus Vision Model 1000 4-16X50 Illuminated 30mm Rifle Scope.
c. Leupold 3.5-10X40 Mark 4 LR/T Illuminated 30mm Rifle Scope.
d. IOR 2.5x10-42 FFP Illuminated Tactical 30mm Rifle Scope with Metric Knobs.
e. USO scppes.
III. Aimpoint Vs. EOTech.
A. Reticles:
1. Aimpoint 2MOA vs 4MOA:
a. For 0-50 yards: 4MOA.
b. For 0-300+ yards: 2MOA.
c. For use with a magnifier: 2MOA.
2. EOTech:
a. Standard EOTech reticle has a 65MOA outer circle with a sub-MOA dot in the center.
b. New reticle on the 557 model is similar to the regular EOTech reticle but has BDC markins for 400, 500, and 600 yards.
3. Conclusion:
a. IMHO, hands down, the EOTech reticle is the clear winner. It has the small center dot for precision and the outer ring for speed (just place the outer ring center mass on the target and pull the trigger.).
b. Note on the reticles: I have read too many times where people indicate that the EOTech or Aimpoint reticle is too fuzzy and they can't get used to it. If your reticle is fuzzy it is because you are using the optic incorrectly. A red dot is not like a traditional iron sight where you concentrate on the front sight. With a red dot, you keep both eyes open and you look through the reticle and at the target. Don't concentrate on the reticle. I also have a stigmatism in my dominant eye and when I wear glasses, I've had no problems shooting as described above.
B. Battery Life:
1. Aimpoint:
a. M2: 10,000 hrs.
b. M3: 50,000 hrs.
c. M4: 80,000 hrs.
2. EOTech:
a. N alkaline batteries: 200 hrs.
b. AA batteries: 1,1oo hrs.
3. Conclusion:
a. The aimpoint wins in this category. You can leave your Aimpoint on all day for a whole year. The EOTech has a 4 and 8 hr automatic shut-off which is great just in case you forget to shut off the optic.
C. Ruggedness:
1. Both of these optics are proven in combat, but I'd still give the slight edge to the Aimpoint because of less reported incidents where it has failed. Some of the earlier EOTechs had some issues, but the newer models are fine.
D: Final Thoughts:
1. For Military purposes, I can see why the Aimpoint is used the most. Great battery life and proven ruggedness. For LE, where a lot of entry work is done, the EOTech shines because of the reticle and battery life is not as big of an issue. With the addition of the new EOTech 557 with 4x magnifier, I think you will see more EOTechs being used by the Military. It is like having the close up speed of a red dot with the magnification and BDC of the ACOG.
IV. CONCLUSION:
There is no perfect optic from 0-1000 Yards. What you have to do is choose the one that is best for your needs. The closest thing that I have found to be ideal from 0-600+ yards is the Swarovski Z6i 1x6 with illuminated Circle Dot.
NOTE: These are just my views on the various optics that are available. If there is something you feel is incorrect or disagree with, please let me know and I'll look at it.