I'm putting a Bushnell AR Optics 3x9x40 on my M&P Sport. As you know if you're familiar with this scope, the black dots on the lower reticle indicated holdovers for 200-500 yards.

My concern is, and I can't find this data ANYWHERE, what do they assume is the distance between the bore and the scope? On ARs like this you need to mount it 2 to 3 inches high to clear the front sight. That significantly affects the bullet trajectory. So I'm wondering what mounting height they're assuming for those black dots to work accurately.

I would guess that they use about 2.5in sight over bore which is standard, and is +/- about 1/10in for most all AR one piece scope mounts. You could call Bushnell but I'm guessing no one answering the phone would know. Try.

I would think that as long as the center dot or reticle is lined up at the correct distance the rest should be good to go, no matter how the scope is mounted.

I was looking at a Nikon scope very similar to the Bushnell. Looks like the same reticle. There is a Nikon app for their scope which may work also for the Bushnell. Try this:

Nikon Spot-On Program and Tools

Brother, you said it. Bushnell tech support said it doesn't matter how far above the bore the scope is mounted; it's "based on the trajectory of the bullet, not how high the scope is mounted." Sigh....... that being said, I can't help but wonder how they designed and tested the reticles. I guess I'll just have to try it at 200 yards and see how well it works.

You got my curiosity up...

I've got a Bushnell AR scope in a box I've never used.

Bushnell recommends the scope be mounted "as low as possible".

About low as possible on any conventional rifle is around 1.5in sight over bore. AR is usually around 2.5in.

The reticle is designed for 100yd zero. Now according to my handy dandy ballistics calculator that puts you...

1.5in / 2.5in

Approx.
200yd 3in / 2in low
300yd 12in / 10in low
400yd 29in / 26in low
500yd 55in / 52in low

Interesting. So there's a 1-inch difference at 200 yards. You talking about 55 gr. .223 there, right? That's within tolerabe limits on a coyote up to 300 or so yards. Thanks a lot for that data - I just hope it's correct!

That 3x9x40 optic if mounted with a standard AR mount. Like a M-223 or the Burris PEPR You will never see the front post. Trust me.

You don't need to go above the front post.

Absolutely No Reason to lift it up 2-3 inches

I used 62 but it will be close.

Use this. And be sure to click on "Advanced Options" to enter sight over bore and any other details.

Ballistic Calculator GunData.org

Very true. I have a vortex crossfire ii 1x4x24 with the Burris P.E.P.R mount, and at any setting above 2x I don't see the front post, and even 1.5X it's just a ghost image.

__________________
M&P9/9C/Shieldx2/Sportx2/15-22

I have the Bushnell scope with the PEPR mounts on my Sport, and I can't see the front sight at any setting. I was told that would happen, but I was skeptical. However, it works great.

You want the front bell of the scope as close to the barrel as you can get it (with-out the bell touching the barrel) for the best results using and getting the best results from your scope. Your rings also need to be mounted on the receiver and NOT on the barrel for best results.

There shouldn't be any image of the front sight in the scope being that close. "Maybe" a slight ghost image at most if that. But it won't be enough to bother your sighting.

If you have a flip-up rear sight, the back of the scope will clear that when it's folded down.

__________________
THIS WE'LL DEFEND ΜΟΛΩΝ ΛΑΒΕ