EOTech 512 or 516 & riser questions

[royta]

I went to a local gun shop today and looked through a 512 that had an FSB. Whoa, that reticle is right on top of the front sight pin. How much does the 516 raise the reticle above the pin, if at all? I'm guessing that a riser will be mandatory if I want lower 1/3 co-witness.

Tell me about the differences between the 512 and 516. I already know about the raised front portion of the 516 so that it clears standard M4 handguards better. I'm wondering if the entire unit is also raised higher than the 512.


Oh, this will be going on my 16" mid-length.

Thanks.

[DWood]

Two friends just put the 556 (NV model) on their LMT uppers with standard front sights. The front post and Troy flip rear sight are very low in the EoTech. I doubt a riser could even be used with the optic or it would be too high. Keep in mind we haven't sighted their rifles in yet, but I don't expect much change.

The 556 / 516 seems like a big improvement. Left side mounted control buttons, CR123 lithium batteries, and tall enough (I think) to 1/3 co-witness without the additional cost of a riser.

[royta]

I just got off the phone with ADM. They said their QD riser/mount will raise the EOTech 3/8" (yes, .375) of an inch. He said the irons would probably be at the very bottom of the window on a 516 or 556. I do know the 512 gives absolute co-witness. The 516 raises over the 512 by 7mm which is .275 of an inch. I'm not sure if that equates to actual lower 1/3 co-witness, but I certainly want to get the sights down low in the window of an optic, but still usable if the optic were to fail.

I like the idea of the 516 over the 512. However, I want to make sure the .275 over absolute co-witness is enough for me. If it's not, than it sounds like the a riser might not work with the 516. I like the idea of a QD return to zero mount, but the QD feature isn't an absolute necessity. I simply want to be able to remove the EOTech from my rail and reinstall it with no change in zero. According to EOTech, the 512 has 1 MOA return to zero (http://www.eotech-inc.com/product.php?id=9&cat=1). The 516 doesn't have any specs listed (http://www.eotech-inc.com/product.php?id=21&cat=1).

Hmm, I have a lot to think about, and right now my rifle haz zero rear sights, let alone any optics.

[RD62]

I'm currently running a 512 on my 10.5" LMT with fixed front and rear sights, and once you get used to it, it's really not an issue and the irons are immediately available if the optic fails.


-RD62

[royta]

I like the idea of the 516 , but I'm wondering about it's return to zero when removing & reinstalling. The 512 only has 1 MOA return to zero when not using a QD riser/mount, and I'm guessing the 516 will be the same. I guess for CQB, that's nothing to complain about, but I'd still like something a little closer. What is an ADM mount's return to zero? Unfortunately, it doesn't sound like a 516 can be used with a riser/mount.

I called ADM. I didn't get the person's name, but he said their EOTech mount will raise "about 3/8" of an inch". I could be wrong on hearing "about" though. Still, .375, or something around that, is one heck of a jump. It doesn't sound like it would be usable with the 516. The 516 raises .275 over the 512. Couple that with a Larue at .275, a YHM at .300, or an ADM at .375, and that optic window is getting really up there. Sounds like too much to co-witness at all. What do you think?

I don't like the absolute co-witness. I have zero real experience with it, but the one single time I spent 1 minute looking through a 512 with a FSB, I didn't really like the FSB obstruction. Have you looked through a 516 on an upper with a standard F-marked FSB? I'm wondering if the .275 over the 512 is enough for me. Admittedly, I'm very used to using magnified optics on a bolt-action rifle, something that has zero obstruction. Perhaps the optics with an FSB is simply something I will have to get used to.

So, it sounds like it's a 516 and live with the 1 MOA return to zero, or a 512 with an ADM mount. That is if it has a tighter return to zero. If not, then there is no real reason to go 512 over the 516.

[DWood]

In my opinion, if you raised the 516 any higher by using a riser, the irons would be barely visible, if at all, through the optic. The idea is not to have to take the optic off at all. You have enough questions that I would not buy until able to look through one for yourself.

One dealer told me the built in rise in the 516 wouldn't be enough for a 1/3 co-witness but when I looked through one for myself, I believe the irons are very low in the EoTech window. You are going to have to get hands on to answer this.

[RD62]

I'd then go for the 512 in an ADM mount.

In fact I'm really interested in trying out an ADM mount when they come out, to see if I like it better.

So, if your listening ADM, come on already!!! :D


-RD62

[royta]

DWood, I think you're right. I'll admit I'm almost forcing myself into a hasty decision because I currently have no optics or rear sight on my rifle. I want the repeatable zero because I plan on swapping back and forth between the EOTech and a 2X-7X scope. EOTech was closed today, so my question on repeatable zero with the 516 will have to wait until Monday. That will determine if the 516 is even in the running. Geez, I over think everything.

[yugolover]

If you go to the service and support section of there website you can find the 08 catalog. It lists all the specs for the 516.

[royta]

Thanks yugolover. I downloaded the brochure and see the return to zero is 1 MOA.

Does anybody have the GG&G Accucam for the EOTech. They are quoted as saying, "In tests, the EOTech Accucam Locking Lever System has shown to be repeatable to less that 1/2 MOA."

[Highway 55]

I just bought a 516. With the rise integrated into the mount it does put the front sight post in the lower 1/3 of the glass.

ETA: I am also curious about the GG&G accucam for the 516. QD w/ repeat zero would be nice.

[VA_Dinger]

I'm currently running a 512 on my 10.5" LMT with fixed front and rear sights, and once you get used to it, it's really not an issue and the irons are immediately available if the optic fails.


-RD62

I would have to agree.

I'm running a 552 with HK416 10.5" fixed sights. Once you get used to the absolute co-witness it becomes a non-issue.

Now I actually prefer absolute co-witness whenever possible.

[royta]

I just bought a 516. With the rise integrated into the mount it does put the front sight post in the lower 1/3 of the glass.

ETA: I am also curious about the GG&G accucam for the 516. QD w/ repeat zero would be nice.

I did a search on ARFCOM for threads with "accucam" in the subject title. I asked a couple users in those threads whether their experience supports GG&G's claims of 1/2 MOA return to zero. They had no disagreements with their claims, so I think the 516 sounds like the hot setup for me. I plan on getting a 2x-7x scope and a ADM Recon-X mount and swapping back and forth between the two optics depending on what I'm doing. I didn't want to have to rezero the EOTech.

[82ndtrooper]

Personally I wouldn't think if running of my 512 without the LaRue Tactical ECOS mount. Just enought rise to co-witness with the irons in the bottom 1/3rd of the field of view and QD type lever to remove it in just seconds.

[jmart]

If you want QD and return to zero capability, then I'd go with a 512 and a LaRue mount. The 516 already has the rise built in, but you won't get good enough RTZ capability, if you intend to swap it out w/your 2-7X scope.

Another option for magnification would be the 516 and an Eotech 3X or 4X magnifier. But now you're adding several hundred dollars to the setup, between the magnifier's mount and the optic itself.

If you go with a 512 and LaRue mount, and then you later opt for a magnifier, you may have a bit of a problem getting a magnifier mount that lines up exactly with the 512. If I'm not mistake, the height of the 516 was engneered to work with either a 3X or 4X magnifier in an Eotech mount.