I cant decide between the two so i'm going to the hive.  Everything I have flashlight on duty belt, shotgun light, ar light uses CR123 batteries.  My buddy who works with me, is adamant on getting the 557 which has AA batteries.  I told him that i'm leaning towards the 556 because if im on a scene, i dont want to search for a specific type of battery i want them all the same.  However, since im getting a new stock that holds batteries im not sure which sights i want and am now indecisive...what say you...?  

EOTECH 557



Buttons on left side to work specifically with NV or magnifiers
AA Battery model (supports Lithium or Alkaline)
Ballistic reticle specific to .223 caliber munitions
Compatible with Gen I-IV Night Vision Systems (tandem operation)
Raised 7mm base compaired to 512 and 552 models

EOTECH 556



Buttons on left side to work specifically with NV or magnifiers
CR123 Lithium Battery model
65 MOA / 1 MOA dot
Compatible with Gen I-IV Night Vision Systems (tandem operation)
Raised 7mm base compaired to 512 and 552 models

I voted for pie...

Of course, pie is delicious, especially in it's peach or apple configuration. I don't have to worry about batteries or buttons, I just open my pie hole and stick in part of the pie and chew.


Pie, it's like my favorite thing, next to steak.








eta: I'm in complete lust over the 557, and if I had the $$ I'd have one to mount on my M1A scout and add in a 3x.

Sadly, I don't have that sorta cash, as I'm still adding chunks to my AR.

I don't think you'll have a problem "searching" for AA batteries amongst your gear.  It's not as if they look anything at all like CR123 batteries.  You will know exactly where in your gear you are storing batteries so I wouldn't expect it to be a problem.

On the flip side, AA batteries are a little easier to find in stores than CR123.  CR123 are still pretty common but not as common as AA.  They also make rechargeable AA batteries.

Or, you could also get an Aimpoint and forget about batteries for the next 5 years

on a duty rifle......... the 556 for you.

you don't need a 600 meter site............ and you are already packing 123's.

i voted 557 but i like this explanation here

Have you looked at a 557 reticle?  Not on your computer screen, on the actual unit.  The BDC is nowhere near that clear and defined.  It just looks like a messy line, a dot matrix display with the dots too close together for anything useful.  It's nowhere NEAR as clear as the picture in your post.


If you want an optic with a BDC, get an acog.  If you want an eotech, get the traditional reticle.

when i first got my 557 i thought to. then i got off the couch and shot with it outside. the natural light clears up the blur for me.

maybe in lower light, but in sunlight, turning the intensity up to see it enough, it's too blurry.

I was thinking the same thing, as the majority of my contact will be within 50ft or so.  Thanks.

I started out with the 556 and ran it through a carbine course with my S&W MP15. Loved it.  Then got four 557's with the 4x magnifier (came as a set, and Eotech was not making the 4x magnifier anymore so I grabbed all the store had) for some of my other AR's.  After having run both the 556 and the 557, I much prefer the 556.  Also have an aimpoint T1 on one of my other rifles.  Haven't run that through a course yet but I think that that will be my favorite.  Reason being is that the single dot reticle whether it is an Eotech or and Aimpoint makes target acquisition that much faster.  I haven't found the bottom three dots/reticles on the 557 useful and are more of a distraction, especially with rapid target acquisition.  If I'm gonna shoot distance I'll use my Leupold on the carry handle of the 20" Colt.

ETA: If anyone wants to trade their 556 for a 557 (sight only not magnifier) pm me and I'll consider it. Tx.