AR-15...Scope+Front Sight=Proble?


August 27, 2006, 07:30 PM
I have an M4 A3 type AR and I would like to mount a magnified scope on the built in rail. Will the front sight present a problem? What height rings should I use?

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Don't Tread On Me
August 27, 2006, 07:41 PM
Depends on the magnifcation. The lower the magnification - the wider the field of view - the greater the chance you'll have the front sight interfere, causing a blurred dark shadow at the bottom of your scope view. Usually 4x scopes or scopes in that power range will interfere unless you get up over the sight, which would be a VERY tall mount - too tall in my opinion. If it is going to be higher power, you'll most likely "miss" the front sight post due to the narrower FOV. You can see this on variables mounted to AR's. On 3x you'll get that black blurr..and as you crank up to 9x the post leaves the view.

For rings, regardless of any other factor - you should get the tallest rings possible. These will give you a decent cheek-weld. Anything short of extra-high rings will force you to tilt your head a lot to get your eye in line with the scope. You'll have an angled view. Not ideal. That's the major drawback of the AR..because of it's recoil reducing in-line makes it difficult to easily see through a low mounted scope.

Best way to figure out the best height is to get scope rings that will raise the center of the scope to where iron sights would normally be. Typically high or extra-high rings are ideal. Of course, there's no standard out there. One company's extra-high are like anothers high.

Ah, another thing. Normal rings are going to typically be short - thus my recommendation for extra-high. Most rings marketed as "tactical" are by default, a lot taller. So a medium tactical ring might be enough, or a high tactical might be enough. There are differences in heights and standards from company to company in tactical rings too.

Some companies sell scope mounts that either bolt onto the rail or attach via quick-detach. The rings are built in to the mount and they position the scope further forward than would be possible if using regular rings directly to the receiver. Why is this important? If you have a scope with BIG will need to be mounted a bit more forward. Otherwise, you'll be placing your head back on the buttstock to get a good view and that will be contradicting with a proper shooting stance......

August 27, 2006, 08:16 PM
I use optics on my ARs all the time. I use fixed front sight bases. I can't see the front sight at all. One of the scopes I most commonly use goes down to 2x.

I just purchased a scope that goes from 1x to 4x. Now I see the front sight with magnification turned off. I'm going to use this scope on my FAL because it was a little annoying.

If you aren't going to use a very low power scope, you won't have a problem.

August 28, 2006, 01:53 PM
1. You NEED at least one AR with open sights.
2. This is a great excuse to buy another AR or just an upper with no front sight, removable front sight, or flip up/down front sight.
Richard (

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