Can I Zero a 2-dot EOTech XPS2-3 @ 25-300yrds

[CogitoErgoArmatumSum]

I recently picked up an EOTech XPS2-3 from a buddy of mine. I have always used a 300yd. zero on all my rifles. However, being that this particular EOTech has the two separate 1MOA dots that are designed for a 50-200yd zero on the first dot and corresponding POI/POA of 500yds on the second dot, my questions are these...

If I were to zero the first dot at 300yds, what would be the corresponding zero on the second dot?

What about the bottom of the 65MOA ring that is zeroed at 7yds if the first dot is zeroed at the suggested 50-200?

Is the 300 yard difference between the 50-200yd zero on the first dot and the 500yd zero on the second dot held constant, regardless of the first dots zero?

I usually shoot 55gr. 5.56 ammo thru a 14.5" carbine AR, how much does this change all the above numbers?

I appreciate any help y'all might be able to provide--I'm just now getting into the science of ballistics, so I apologize for the hand holding.

[PatrioticDisorder]

50/225 or 100 yard zero are both light years ahead of a 25/300 yard zero.

[JSantoro]

We have a stickied thread in AR General regarding comparative zeros, partially to keep the tastes-great/less-filling arguments that swirl around them somewhat centralized. Let's please keep it that way.

https://www.m4carbine.net/showthread.php?t=65679

As for that second dot, it's about 10MOA below the center one, which is 10" lower than the center one @ 100yds, and can be extrapolated for distance from there.

The 2nd dot is advertised to provide a 500 aimpoint...and it may very well do just that, but not universally; there are variables, mostly that of ammo used. EOs aren't "recipe" optics, but the descriptions as to center dot=x distance/low dot=y distance would be based on M855. Talking about 500 yards or meters, 55gr ammo will print differently. How much? Check the above link, there's charts all over that thread that provide for differing ammunitions AND different zero methods, and can give you an idea.

You can chart it and have a very educated guess, but can't be certain until you shoot the thing at those distances.

No, if you zero the center dot in such a way that lower dot provides for a 300 yard difference, then you will get a different such distance of you elect to zero the center dot in a different fashion.

As for the base of the circle, yes, that's commonly used to account for the mechanical offset of the sight's height over bore for close-in shots.

[ra2bach]

:D

I don't have a ballistics calculator but maybe someone who does can help out here - the second dot is listed at -2.8 mils or -9.7moa.

or here's one if you have the time...

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

good luck...

:dirol:

[CogitoErgoArmatumSum]

We have a stickied thread in AR General regarding comparative zeros, partially to keep the tastes-great/less-filling arguments that swirl around them somewhat centralized. Let's please keep it that way.

https://www.m4carbine.net/showthread.php?t=65679

As for that second dot, it's about 10MOA below the center one, which is 10" lower than the center one @ 100yds, and can be extrapolated for distance from there.

The 2nd dot is advertised to provide a 500 aimpoint...and it may very well do just that, but not universally; there are variables, mostly that of ammo used. EOs aren't "recipe" optics, but the descriptions as to center dot=x distance/low dot=y distance would be based on M855. Talking about 500 yards or meters, 55gr ammo will print differently. How much? Check the above link, there's charts all over that thread that provide for differing ammunitions AND different zero methods, and can give you an idea.

You can chart it and have a very educated guess, but can't be certain until you shoot the thing at those distances.

No, if you zero the center dot in such a way that lower dot provides for a 300 yard difference, then you will get a different such distance of you elect to zero the center dot in a different fashion.

As for the base of the circle, yes, that's commonly used to account for the mechanical offset of the sight's height over bore for close-in shots.

JSantoro, thanks for your help and the thread! The thread seems like a wonderful resource. I apologize if my original post was a superfluous carbon copy of a previous post, or not placed under the correct category.

Before placing my original post, the various searches I conducted yielded a wealth of information that I am still trying to learn and understand. However, (probably due to my novice status) I did not find anything that addressed this specific question--thus why I decided to post. I usually try to ask technical and/or equipment specific questions--I assure you that I have no intention of mucking up the web with even more inane banter about subjective arguments and opinions.

As to your point about the EOTech's advertised zero's, I did notice that they were M855 specific, and I believe it even mentions 2900fps. I usually can only pick up the M193 and I have a 14.5" carbine barrel (I read somewhere that I should expect around 3050fps, with that kind of set up and ammo, is that about right?)

This whole question was the result of trying to set up my latest rig with a lower 1/3 co-witness, before realizing that optic is specifically designed for a 50-200yd zero (provided the gr. and fps. are as specified) on the center dot and my iron's are set up for a 300yd zero. Anyhoo, thanks again for the help!

[JSantoro]

I apologize if...

You've absolutely no reason to do so.

I didn't entirely cite that thread for you, but mostly for the guy that apparently thinks that the answer to "How many ounces are in a pound?" is "Alaska."

The absence of a Dueling Banjos conversation about different zeros, or a request to evaluate such, in the original post is no reason for him to artificially introduce one.