MeprolightM21 Day and Night Reflex Sight, Self-Powered Dot Sight with Tritium, Fiber Optics, No Batteries Required, Made in Israel

Comparison of the two premier tritium powered 1x optics.I own both the Acog reflex and M21 now and I have to say it's a very tough choice which I would chose over the other.Main problem with both:Washout- these are powered with fiber optics and tritium. When it's dark, the tritium illuminates and reflects of the lens. When it is bright the fiber optics collect the light and then reflect it off the glass. So more light, a brighter reticle. Less light, a dimmer one.When shooting from a shaded or darker area, this is where the issue occurs. It is collecting little to no light and not producing a bright reticle. So if you were to aim the optic out to a brighter area, the reticle will disappear (washout). You are unable to see it and aim.Best at combating washout?Winner: Acog ReflexI own the bullseye model of the M21 and amber dot of the Acog. The color in the Acog is much richer and darker. The M21 is much lighter. In situations where the dot would wash out on the M21, the Acog was still visible. And if I took it to an extreme and pointed both at a light and covered the fiber optics up... Not an issue for the Acog***main let down of M21***No Polarizing Lens!!!The Acog comes with a lens that lets you adjust the opaqueness of the lens (like transitioning glasses). If it is bright out and you're shooting from a poorly lit area, you can use this lens to darken it and... You can clearly see the reticle. The fiber optics for the Acog sit at the front of it while the M21 is situated on top. So the type of light that you are shooting into will affect the reticle more on the Acog while the light your are shooting from will affect the M21 more.I have not been able to find a polaraizing lens for the M21. There is a washout remover that is available ( but requires batteries) which defeats the purpose of this type of optic.The lack of this lens is about enough for me to choose the Acog over the M21 even though I would say the M21 is superior in almost every other area. Build, feel, reticle, size, & bang for your buck.The M21 comes with a QD mount where you will have to spend another $100 for that on the Acog. The metal has a nice finish compared to the rougher texture on the Acog.The reticle type on the Bullseye model is great. Like if the Acog and Eotech had a baby. It's big and can be used for rapid acquisition where the amber dot Eotech will take some practice picking up quickly.Both are built like a tank and are in one solid piece. I do not doubt there ruggedness and would feel safe taking either one with me in the case of fall out.I have also had range time with the micro aimpoints (which are about $300 more) and would still chose either one of these over any red dot. Do. It for get both of these are still used today in combat and you won't go wrong with purchasing them.***side note***I also bought the MX3 magnifier that's goes with the M21.I would chose the Eotech G33 magnifier. The M21's lens has a teal hue that is ver pronounced with the use of a magnifier.

Used the Bullseye reticle M-21 - tossed it on an Arsenal SAM7SF AK in 7.62x39 and did a quick zero.Coming from the world of aimpoint and Eotech, I was curious how it would perform. Ran some CQB and it worked flawlessly all morning. Then for the final actual test, shot 3 shots at 300 meters at a silhouette shaped gong, of the 3 shots 2 hits. Cannot complain. Excellent optic, very clear on an overcast day and works well for a myriad of shooting styles.Pros: Clear Reticle, built like a tank, no batteries required, performs exceptionally at a reasonable price.Cons: Washout is real - it’s not a game breaker though. Lens, mine wasn’t polarized - while also not a game breaker - get a polarized lens option.5/5 will be my standard optic moving forward.

I put this on my Kel-Tek KSG. It is the perfectly complemented sight system for that weapon. Quick, smooth and tough. I sighted it in at 40 yards for slugs, and it shoots perfect tight patterns of .00 Buck at 15 - 20 yards. It's like firearm and sight system were made for each other. I added some flip up iron sights as a backup and am set.I like it so much I ordered a second one for a 9mm. carbine I own.Update: 04-04-16 - Ordered a second Meprolight M21 and mounted it on my UZI semi-auto carbine. Another perfect match. it was simple to mount on both weapons with the right hardware, and very quick to sight in.I don't know what the few others are complaining about as far as "washout'. I live in Nevada, shoot at an outdoor range, and practice low light transitional building clearing (light to dark to light). I have no problem. I love this optic system. You just have to know what it is, and how to use it.It is rugged, tight, clear, and tough. Quick to acquire the triangle and point of aim on the target, with both eyes open, while on the move.It is not an ACOG, nor is it trying to be one. For me, it fits into the category of the EOTECH. I am very pleased with these purchases.

This is a nice optic heavy duty always on. The only issue is when there is not much ambient light, such as when the your target is in a well lit environment and you are in the shade, the retical can have washout and be very difficult to see. Outside, in a well lit or very dark environment this optic is nice and fast. Intermediate lighting is its challenge due to no batteries to increase the retical brightness. If you want something that is always on and works well in most lighting situations this is a good choice. The triangle retical is also nice allowing you to sight in the top point of the triangle for distance targets. This optic is a compromise between a red dot and iron sight, better than irons not as good as a red dot when the batteries work, but way better than when your red dot batteries die.

I have a couple ACOG's and this sight. Between the two I really don't know if I could pick a "better" or "worse". The M21 is, like the ACOG, simple. It is also cheaper.I purchased the REM21 and polarizer with flash guard. I use the latter on the ACOG's as well and have been testing the REM ACOG with great results. The flash guard isn't really needed unless you are worried about the flash, the polarizer is nice to have installed and the REM's are just a "no brainer" especially on the M21 as it does not hinder any of the good things the sight does while adding really great things to it!Which would I buy if I could only have one of these sights? Tough call as I know the ACOG well and only just getting into the M21. The price point on the latter is better but the ACOG is a really solid sight. I really can't help with that dilemma.