Why are scopes mouted so high on AR's?

[bwframe]

With precision bolt action rifles, it seems as though the idea is to mount the scope as close to the bore as possible. Leupold even designed a scope with a cutout to set lower.

Why is it that all the pics I see of scoped AR's, even the heavy barreled ones, seem to be mounted way higher than they could be?

 

[BloodEclipse]

Bolt action rifles and most other semiauto rifles have one thing in common. The buttstock drops at an angle giving a lower cheek rest. On the AR the stock comes straight out the back to accomodate the buffer tube.
Ever notice even the iron sights on AR are higher than regular rifles?

 

[Ri22o]

You also need to have enough room to reach in and pull the charging handle back.

 

[melensdad]

With precision bolt action rifles, it seems as though the idea is to mount the scope as close to the bore as possible. Leupold even designed a scope with a cutout to set lower.

Why is it that all the pics I see of scoped AR's, even the heavy barreled ones, seem to be mounted way higher than they could be?

There are multiple reasons:

• Many have flip up aux. front and rear sights, the guns with those back up sights need to have the scope mounted so they see above them when they are in the folded down position.
• Many have a front sight with a flat top rail so the scope has to see at the same level as the front sight, or slightly above it so that the scope is not obscured by the front sight.
• Many have large front objective bells and need to be raised above the barrel for clearance.
• Many have a carry handle and need to have the scope mounted to that, so by default it places the scope high.
• There are a couple brands, Leupold is one, which you mention, that has the scalloped lower portion of the front objective and that can be mounted lower.

There are probably a few more reasons too. So it really just depends on the scope and the configuration of the rifle as to how the scope is mounted. I have an AR 9mm Carbine that has a raised scope to see over the front sight. My daughter's AR has a carry handle and the only way to mount a scope is on top of the carry handle. I have a long range AR rifle that has an ultra low mount that allows for the objective to be within a 1/2 inch of the top of the barrel. Below are photos of 3 of my ARs, they show the differences in scope height from extreme high (mounted on the carry handle) to extreme low (ultra low rail mounts only 1/4 tall). In any case, the charging handles can be reached under the scope if the scope is mounted properly. If you need further examples I could go shoot photos of all my various ARs and their configurations but these three are good illustrations.

 

[melensdad]

Bolt action rifles and most other semiauto rifles have one thing in common. The buttstock drops at an angle giving a lower cheek rest. On the AR the stock comes straight out the back to accomodate the buffer tube.

The elevated sights actually force you to use an elevated cheek piece to get your head up to the scope level when the scope is mounted high. Its basically a bad design to have the scopes so high so the adjustable stocks and the marksman cheek rests were added to raise your eye up to the scope level. Take a look at any of the photos of our snipers using AR pattern guns, they have to add an elevated cheek rest to bring their head up to the scope when the scopes are mounted high . . . but if you see them with a low scope then they don't need to raise up their cheek at all.

The guns were designed for shooting without scopes. You can get a good cheek weld to the buttstock using a standard A2 buttstock with your eye on target lined up with the iron sights. Add a scope and that is where the design sort of fails. Again remember these guns were designed 40+ years ago when scopes were simply not as common as they are today.

Ever notice even the iron sights on AR are higher than regular rifles?

This is because of the top mounted carry handle. The sights are integrated into the carry handle, that elevates the sight. The flat top guns with flip up sights don't suffer from this same problem. A bit of history here, the carry handle was asked for by the military, it was incorporated into the design in the 1960s and just stuck, there is no reason the sights NEED to be so high other than the design issue.

 

[rhino]

Bolt action rifles and most other semiauto rifles have one thing in common. The buttstock drops at an angle giving a lower cheek rest. On the AR the stock comes straight out the back to accomodate the buffer tube.
Ever notice even the iron sights on AR are higher than regular rifles?

This is the correct answer.

Because of the buffer tube, the stock on an AR has to be straight. When you have the rifle mounted properly (nose to charging handle, head as upright as possible), the sights have to be a couple of inches above the boreline. Otherwise you'd have to scrunch your head down to the stock. The same goes for red dots or telescopic sights mounted on flat tops.

Some people can manage with scopes closer to the bore based on their body configuration, typically if they shoot from a bench. That's not the norm for a weapon designed for battle, however.

Scopes mounted on top of carry handles are okay for plinking at the range or for shooting at known distance targets. They are a bad idea fo a gun used for more serious purposes as it exacerbates the holdover required due to the offset between the boreline and the line of of sight.

 

[Dave]

Scopes mounted on top of carry handles are okay for plinking at the range or for shooting at known distance targets. They are a bad idea fo a gun used for more serious purposes as it exacerbates the holdover required due to the offset between the boreline and the line of of sight.

 

[BloodEclipse]

If you look at my avatar the scope on the one AR and the Bushnell Holosight (as well as the flipup sights) are both 1.5" (centerline) above the rail. I had to order a set of Extra High rings to get the scope to set there.

I'm not sure they make sights for the AR that would sit flat against the rail like iron sights on other types of rifles, because of the cheek weld problem.

 

[melensdad]

If you look at my avatar the scope on the one AR and the Bushnell Holosight (as well as the flipup sights) are both 1.5" (centerline) above the rail. I had to order a set of Extra High rings to get the scope to set there.

I'm not sure they make sights for the AR that would sit flat against the rail like iron sights on other types of rifles, because of the cheek weld problem.

With an optic with no magnification or less than 1.5X, the best system is to work the optic with the open sight at the same time, or at least have that option available in seconds if something should happen to the optic.

The two pics below are an example of working the optic with the open sights (EO Tech sight). This way, if the battery in the EO Tech goes dead, I can use the open sights without doing anything at all. Good to go.

 

[Bigum1969]

This has been a very informative thread. As a recent owner of my first AR type rifle (Sig 556), I wondered the same thing.

In fact, my ACOG sits high, but I've got a Doctor Optic red dot that is mounted on top of the ACOG -- even higher!

 

[esrice]

556 + ACOG

Boy you sure picked a nice "first rifle".

lol

 

[Bigum1969]

I have really enjoyed the rifle and the ACOG. I had the chance to take it out today and run a few hundred rounds through it.