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bp805
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Posted: 12/12/2009 8:02:35 PM EST
Looking to buy my first EOTech and trying to decide between the 516 and the 512/XPS2-0 to use with a BUIS. I know the 516 has a lower 1/3 cowitness and the others are standard cowitness. Can anyone post some pictures of a 516 sight picture (or any other model that has a lower 1/3 cowitness) and a standard cowitness from a 512/XPS? Id like to be able to compare the two sight pictures to see which I like best before I buy. Also, Id like to hear some pros and cons of each and why. It will be used for law enforcement and most likely wont be taking any shots longer than 100yds. Thanks for the help!
Saiga12MD20
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Posted: 12/13/2009 12:35:04 PM EST
[Last Edit: 12/13/2009 12:35:54 PM EST by Saiga12MD20]
I have a 512 with absolute co-witness. It doesn't bother me but I am still going to buy the YHM Eotech riser to try out. It raises ithe sight .300" for lower third co-witness and only costs about $30. If you go the same route I did, at least you can pick between the two, versus just having lower-third if you go with the other.
PC-Tech
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Posted: 12/13/2009 1:01:39 PM EST
Here is my 517, same as the 516 but buttons on the side.
jeepinnc
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Posted: 12/13/2009 1:20:16 PM EST
How do you know which models have a lower co witness?
PC-Tech
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Posted: 12/13/2009 1:52:17 PM EST
Originally Posted By jeepinnc:
How do you know which models have a lower co witness?


The spec will say Raised 7mm base. I was also wrong about the 516, the difference is that it uses the CR123 instead AA, both have the buttons on the side.

jeepinnc
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Posted: 12/13/2009 6:14:07 PM EST
So, I have the 551. Does that mean I need a raised mount for it?
SuperSet72
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Posted: 12/13/2009 6:35:50 PM EST
Originally Posted By jeepinnc:
So, I have the 551. Does that mean I need a raised mount for it?


Yes, if you want 1/3 cowitness, you'll need to buy a riser.
bp805
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Posted: 12/13/2009 6:50:50 PM EST
The only thing that worries me about the lower 1/3 cowitness is having the iron sight picture so low in the bottom of the window and having the area below the window block out what I am trying to aim at and losing some of the area around the target compared to a standard cowitness. Especially if Im trying to acquire a sight picture very quickly. I have never tried out the 516 to check this out to see how I like it, I guess I should before I buy. Is my concern really an issue in the first place? Has anyone else had that feeling? Any more pictures out there? Thanks.
jeepinnc
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Posted: 12/13/2009 6:58:05 PM EST
Can someone explain to me the 1/3 cowitness or point me in the direction of a thread that does?
PC-Tech
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Posted: 12/14/2009 5:00:18 AM EST
Originally Posted By jeepinnc:
Can someone explain to me the 1/3 cowitness or point me in the direction of a thread that does?




absolute (left) and lower-1/3 cowitness (right)

On both the dots line up with the site.
jeepinnc
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Posted: 12/14/2009 7:43:47 AM EST
Thanks, PC.

In either case the point of impact is the same, correct? Is it just a preference where the irons fall in the optic window?

Where about are you in NC, I am in the Charlotte Metro. Sorry about hijacking the thread OP.
bp805
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Posted: 12/14/2009 7:57:45 AM EST
No problem. Im still trying to figure out what the point of lower 1/3 is other than not having the front sight post always being right in the middle of the window when you are trying to aim. Are there any other reasons for the lower 1/3 or just preference to get the front sight post lower in the window?
nihilsum
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Posted: 12/14/2009 9:58:09 AM EST
[Last Edit: 12/14/2009 10:04:12 AM EST by nihilsum]
Originally Posted By bp805:
No problem. Im still trying to figure out what the point of lower 1/3 is other than not having the front sight post always being right in the middle of the window when you are trying to aim. Are there any other reasons for the lower 1/3 or just preference to get the front sight post lower in the window?


I think that about sums it up. Keep both eyes open and the 512/no riser will be fine.

ETA: I went through the same debate. I ended up getting the 512 and YHM riser so I could just sell the riser if I did not need it. Tried both configurations for a while and found the riser not necessary.

It is psychological, but for some reason I prefer lower 1/3rd with Aimpoint and other conventional red dots.
Skyyr
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Posted: 12/14/2009 10:10:26 AM EST
[Last Edit: 12/14/2009 10:10:53 AM EST by Skyyr]
My suggestion would be to get lower 1/3rd only if you have fixed sights. If they're flip up/down sights, then an absolute will serve you better and simply place your irons in the down position while shooting.

Remember, the higher you place a sight above the bore, the more compensation that is required for longer (or shorter, depending on your zero) shots.
PC-Tech
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Posted: 12/14/2009 1:02:51 PM EST
Originally Posted By jeepinnc:
Thanks, PC.

In either case the point of impact is the same, correct? Is it just a preference where the irons fall in the optic window?

Where about are you in NC, I am in the Charlotte Metro. Sorry about hijacking the thread OP.


Yep, same point of impact. I think you get more picture through the window if you have a fix site. Remember you're not going to aim looking through the rear site, you are just going to put the red dot on what you're going to shoot.

I'm in Charlotte Metro (Huntersville) and drive a Jeep too.
FALCON1
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Posted: 12/14/2009 1:14:02 PM EST
I am in the same situation, I have a SBR with MAGPUL BUS front and rear............the EOTECH is sighted on target without them but when I raise the front sight if sits way low of the halo ring on the EOTECH. I tried the POF sight up front and it seems to sit higher and gives me a better picture. I like some on this thread picked up the YHM EOTECH riser and now it sits too high to the point I cannot use the rear MAGPUL. I am almost convinced not to use the rear but just the front sight in case of batter or optic failure.....I may not hit the 10 ring but I will hit a torso sized object metal or flesh.

Any other thoughts on using the riser ? Are the MAGPUL front and rear too low in comparison to others and if so based on the above situration what rear BUIS would help me ?

hubcityraider
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Posted: 3/4/2010 6:00:54 PM EST
Originally Posted By FALCON1:
Any other thoughts on using the riser ? Are the MAGPUL front and rear too low in comparison to others and if so based on the above situration what rear BUIS would help me ?

I wonder about rear site height differences also. I just put a LaRue EoTech riser on mine and my ARMS rear site seems a little low. Still functional, but I would like it to be a bit higher. I think I can see why people would want the lower 1/3 though. I have a front site tower and can comfortably use the red dot in the middle of the screen with very little obstruction. I think that was the point of getting the riser. Originally I just got it to see what the darn deal was.
FAIRLY FLAT TRAJECTORY?!
HenryHill408
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Posted: 3/4/2010 6:27:20 PM EST
I run a fixed front sight and a YHM riser for lower 1/3 witness. I would HATE it if it was absolute co witness, that would just get in the way. Much prefer it in the lower 1/3
hubcityraider
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Posted: 3/30/2010 5:50:45 PM EST
Originally Posted By HenryHill408:
I run a fixed front sight and a YHM riser for lower 1/3 witness. I would HATE it if it was absolute co witness, that would just get in the way. Much prefer it in the lower 1/3


I see what you're saying but I'm not convinced. I've been out a couple times with my LaRue riser on. It certainly opens up the view, but by the time I get my cheek weld on, the red dot is in the bottom of my view thus more of my target is obstructed. I may be doing it wrong though.
FAIRLY FLAT TRAJECTORY?!