Started the AR Optic world with an EoTech and switched to the MRO and been there ever since. I have always had a mount that co-witnesses with my BUIS.

I see more and more folks moving to taller mounts. As I was sighting in a rifle this week I was thinking to myself how it would be nice if the mount were higher keeping my neck and head in a bit more natural position.

Looking at grabbing a Unity mount with the built in rear for my MRO.
Of
Or maybe the SCALR Works at it seems that the base is open and you just use both your BUIS.

Any downsides?

I have mostly unity fast mounts. I wanna say they are the 1.93" mounts so not CRAZY high but I like them more than cowitness. No downsides in my mind.

Looks funky, especially with the eotech and some other optics but who cares what it looks like.

quote:

Originally posted by Black92LX:
Any downsides?

Guys over 60 calling you a Gravy SEAL Larperator.

Seriously, after getting used to 1.93 and 2.26 in some applications, I much prefer it for most long gun shooting. As long as you train to hold for the offset on nearer targets, I think it's a net positive.

^^^^^^^^
Can you explain the offset to me please?

I switched most of my optics to the Scalarworks 1.57" lower 1/3 co-witness mounts. They're nice mounts, no zero shift if removed. I'm not really into the sky-high stuff though.

It was long common for commentators to complain that a scope sight was mounted so high that the shooter had more of a “jaw weld” than a secure cheek weld (or as the Army used to call it, a “stock weld”).

For most of my shooting life I believed that the more pressure between cheek and stock, the better. A few years ago, though, I started shooting 22LR rifles for the dedicated purpose of achieving consistent accurate results on small targets at distance. But although it was a slow process prompted by both comments here on the forum and my own experiences and experiments, I found that light stock/cheek pressure was significantly better for precise accuracy. The contact pressure has to be enough, but not too much.

And yes, how a setup looks can be a surprisingly important consideration. I have mostly gotten over such fears in favor of what works best. Mostly.

To chime in on the “offset” question because it hasn’t been addressed yet, I believe it referred to the distance between the bore of the rifle and the centerline of the sight. Because the sight is mounted above the bore, at short shooting ranges that height difference will cause the bullet impact to be below the point of aim. With an optic that’s more or less in line with a common AR-15 front iron sight, the point of impact can be as much as a couple of inches. The POI difference would be even greater with a sight that was mounted higher.

(Or did you know all that, and have a different question? )

I dont like them. 1.70 is the sweet spot for me on my LPVO. EoTech just mounts direct to pic rail and it works fine for me. I suppose it may depend on body type and intended purpose of the gun. I've seen the taller mounts give guys absolute fits in classes when proned out. The height over bore thing starts to get a little wild, at least for me, when shooting at various distances.

quote:

Originally posted by MikeGLI:
I've seen the taller mounts give guys absolute fits in classes when proned out.

An excellent point that should be kept in mind by anyone who might be shooting from various positions.

The reasoning behind these higher mounts was to help guys who are wearing gas masks, certain NOD setups, or other gear that might interfere with a typical optic setup get a proper sight picture. I'm pretty low speed high drag, but I've encountered this problem when using sims at work with the protective headgear. It gets in the way so you can't get your head down close enough to the stock to see the sights.

Not being someone who has access to that type of kit for real-life, though, I prefer a standard co-witness on my rifles. The sight offset on the AR is already pretty extreme compared to other long guns (one of the few negatives to an otherwise excellent platform, IMO), and I don't see any benefit to making it worse if there's nothing preventing me from achieving a regular sight picture.

I think the tall mount offset is overblown.
Iron sights are already 2.5" above the bore, a little bit more is not that big a deal to me.


I find anything under 1.6" to be unusable for me, dots or scopes.
I first tried a .5" riser and that changed everything for me.
My red dot has a 1.8" tall mount and all of my scopes use a 1.93"
Usable in any position for me with a consistent cheek weld.

quote:

Originally posted by 92fstech:
The reasoning behind these higher mounts was to help guys who are wearing gas masks, certain NOD setups, or other gear that might interfere with a typical optic setup get a proper sight picture. I'm pretty low speed high drag, but I've encountered this problem when using sims at work with the protective headgear. It gets in the way so you can't get your head down close enough to the stock to see the sights.

This is the only reason I can see for needing super tall mounts. I know someone who has one of the tall mounts on his SBR for this reason and hates it when not using NODs.

quote:

Originally posted by MikeGLI:
I dont like them. 1.70 is the sweet spot for me

Same here. 1.70 is the Goldilocks height for me.

And it still allows for a low cowitness with irons.

The only reason that I'd consider a taller 1.93 or 2+ height is if I expected to spend a considerable amount of time using that rifle while wearing a protective mask or NODs.

quote:

Originally posted by Black92LX:
^^^^^^^^
Can you explain the offset to me please?

The short and sweet version is that up close and out to about 20 yards or so, depending, you need to aim a few inches over where you want your round to impact. You need to do this with irons anyways, but adding more height just means you should pay a little more attention to it than you did before. A huge deal? Well, if it's the difference between hitting an A zone vs a C or a D, or clipping a no-shoot target at a match? Then yeah, it matters. Shooting an actual hostage because you're a police officer and your patrol carbine has a huge riser on it than you haven't trained up on? Bigger deal.


As far as "needing" a riser, I was dragged to it kicking and screaming. I was convinced that anything over lower 1/3rd was guys trying to look like "operators" and blah blah. Guys who don't own NV will say that NV and gas masks are the only reason to have an optic height over lower 1/3rd or whatever their cowitness of choice is. The truth is, you can shoot passive with NV through even absolute cowitness setups, it just sucks is all, and most guys are shooting active anyways and the optic is secondary or not even used. The taller optics gained favor with that application in those circles because it's faster. Guess what? What's faster under NODs is faster without them, too. I finally got tired of whacking my objective lens off my top rail and tried a 1.93" height mount. It was really good, and I liked it, and my shooting improved a lot. I tried a 2.26" height mount next. It was really good, and I liked it, and my shooting improved a lot. I am no Grand Master, and I don't shoot as many matches as I'd like, but shooting rifles and PCC's on the clock against other shooters was the pressure I needed to see where my preconceptions weren't translating to reality.

For rifles and carbines that I want to shoot quickly, accurately, and comfortably, there is no going back to the lower mounts for me. Heads up is preferable. Focus on the target, bring the gun to you and not the other way around, get your flash sight picture with the dot and fire. It's just translating the way we use dots on pistols to long guns, and it works.

^^^^^^^^^^^^
That is what I figured was meant. Already working with mechanical offset. Did not expect going from an absolute co witness to this would affect it that much.
When I had the EoTech I would do this by using the bottom of the Circle instead of the dot. Now with the MRO I just aim slightly high at 10 and in.
I guess I did not expect it to be affected much.

I do miss the Circle Dot of the EoTech and next time I buy an optic will likely get the MROHD so I have a Circle Dot again.

Guess, I will eventually give one of these taller mounts a try and make sure to see how much it adds

This message has been edited. Last edited by: Black92LX,

The higher mounts have become a cottage industry for many gear producers. The premise is “you-can’t-be-a-delta/SEAL/ranger” without this new widget.

High mounts were a niche need that became a cool guy statement. The truly ironic thing is when you look at most of the current pictures of CAG or SAS they are using SIG Romeo 4s with a lower 1/3 mount. You know, the guys who do it for a living.

And lastly, most of the guys I see with the tall mounts can’t make a precise shot if their life depended on it. They can’t figure out where in space to aim to make up for the obscene amount of offset.

^^^^^^^^^^^
So outside of YouTube videos I have never actually seen one in use.
Been to a number of rifle courses, trainings, and quals now and never seen one in person.

I just happened to sight in a rifle Wednesday came home and watched the Sage Dynamics video on the Ridgeback Rhodie and he had a tall Mount and LOOKED more comfortable than I was earlier in the day.

I’m not versed in any of the modern “mm or inch”-tall talks. In the old days, what I know was lower 1/3 cowitness, absolute cowitness and the lowest mount for shotguns. So, can you guys translate these into mm or inch heights for me? And I gather that there are taller mounts than the lower 1/3 cowitness one?

And, where does the RMR mounted on top of the ACOG fall in terms of height?

The exact optic centerline height will vary a bit from company to company and mount to mount, but in general the optic centerline will fall at approximately one of these five common heights with AR optic mounts:

1.42" is Absolute Cowitness height.

1.57" is Lower 1/3rd Cowitness height. (Though some companies call their 1.70" mounts "Lower 1/3rd" too...)

1.70" is the next common height, sometimes also called "Lower 1/3rd" as mentioned above, and sometimes just called "Tall" or something else. This is as high as you can go within these semi-standardized mount heights and still have a usable low cowitness with standard iron sights.

1.93" is the start of the extra tall types of mount that are in vogue lately, but now you're into mounts that are too tall to cowitness with sights.

2.26" is the other currently popular extra-extra tall mount height.


A RMR mounted on an ACOG will have its optic centerline at around 3.5", so taller than any of these.

quote:

Originally posted by 12131:


And, where does the RMR mounted on top of the ACOG fall in terms of height?

Mine is pretty close to 3.75 inches height over bore.

^^^^^

All Rogue's numbers are accurate for height over rail. Then add another 1.21" to get height over bore.

The total Unity/2.26" height over bore ends up being 3.475", which is why you need to know the offsets for Point of Aim/ Point if Impact for shots up close.