A Reader Asks About AR-15 Scope Mounts And Front Sight Interference

Reader Joe asks:

I’m Interested in purchasing the VXR Patrol, but want to make sure that my front iron sight post will not be in the way. Will a standard PEPR mount work, or do I need something else? Note: I’m shooting a Smith & Wesson M&P15 Sport.

Excellent question, Joe . . .

Many ARs (including yours and mine) are sold with fixed A2 front sights even though most of us put scopes or reflex sights on them. Removable or folding front sights are ideal for scoped ARs, but fortunately A2 front sights aren’t much of an optical obstacle for properly-mounted scopes.

As you probably know, standard A3 flattop rails aren’t high enough for most scopes or red-dots to co-witness with iron sights. EOTech holographic sights are an exception, since they’re tall enough to co-witness right out of the box. Most other optics will require some kind of riser mount to keep you from looking straight at the rear of your front sight tower, but these riser mounts are readily available and affordable.

This photo shows the VX-R Patrol scope you’re considering, mounted on standard medium-height 30mm scope rings and a $10 UTG riser. This solution is heavy and ugly, but it works. You’ve already hit on a much more elegant solution: a combination riser mount like the PEPR.

Burris’s ‘Proper Eye Position Ready’ mount shown here is designed specifically for AR pattern rifles, and it uses an offset scope ring to move your tactical scope forward and out of your eye socket. The PEPR is a great mount for around $100, but it’s not the only choice.

Leupold (the source of all things good and holy where optics are concerned) sells this bomb-proof Mk. 2 Integral Mounting System for about $150. At the lower end of the market is the $60 Primary Arms Deluxe AR-15 Scope Mount pictured at the top of the article. It has no frills and certainly no name cachet, but it gets the job done: Foghorn and I both trust it.

Any of these raised/offset mounts will lift a scope high enough to use with a fixed A2 front sight tower. The VX-R Patrol’s line-of-sight won’t clear the front sight completely, but you can barely notice it. The front sight will be dimly visible  in the bottom 1/3 of the scope’s field of view at the lowest power (and blurred to near-invisibility), and I can’t notice it at all at higher magnification.

My own AR wears fixed A2 front sights and a VX-R Patrol on the Primary Arms mount, and it works perfectly for me. The PEPR is a great scope mount for the AR, and the combination should work perfectly for your M&P15 Sport as well.

One last tip: if you do decide to go with the VX-R Patrol, be sure to order the PEPR with 30mm  rings.

13 Responses to A Reader Asks About AR-15 Scope Mounts And Front Sight Interference

  1. avatarbrigo05 says:

    Armalite makes great single piece scope mounts as well. ~$90

  2. avatarChris says:

    You refered to Burris as “Bushnell” in your link there.

  3. avatarDrewN says:

    I use GG&G one piece bolt action height mount combined with a GG&G scout type riser. This enables me to run my scopes on any of my platforms with just a small weight penalty. This enables me to get by with only two pieces of premium glass, a 3.5 x 10 and an 8.5 x 25, both Leupold Mk4 front focals with the TMR. I find transitioning between scopes more troublesome than rifles, plus it’s alot cheaper. If I have friends who want to shoot at the same time, I have a few “beaters” in qr rings that I’ve accumulated over the years.

    • avatarChris Dumm says:

      Do you have to re-zero when you move the scope from one gun to the other? I’d expect so, but if not that’s great.

  4. avatarChad says:

    I bought my first AR last week. It’s an Olympic Arms 5.56 and it has a carry handle. If I want to put a red dot sight on an AR with a carry handle, what options do I have?

    • avatarRambeast says:


      This is what you will want, if you have an A-1 configuration upper. Personally, I have come to the conclusion that iron sights are the way to go. Scopes are nice, but not optimal. Remember K.I.S.S. (Keep It Simple Stupid) In a fast paced life and death scenario, scopes can get knocked off zero, covered in mud/grime/etc, lenses can be broken…but iron sights are king, unless you are almost legally blind.

  5. avatarJamie in ND says:

    I have a PEPR on my Stag 6.8 that has a fixed front sight. The scope is a Nikon Prostaff & I have no problems with seeing the sight in my scope.

  6. avatarMike G says:

    I put a Redfield Revolution with Nikon mounts on a M&P15 Sport. At 2x there was a faint shadow from the front sight that I was able to remove almost completely by moving the scope a small distance rearward.

  7. Hey, thks for sharing! Very helpful info here as I recently got my first AR-15. Thks for your tips. Cheers!

  8. Hello i am kavin, its my first occasion to commenting
    anyplace, when i read this article i thought i could also make comment due to this brilliant piece of writing.

Leave a Reply

Please use your real name instead of you company name or keyword spam.