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Burris FF3/ADM22 Mount - how far out on the rail to I put it?

670 Views 2 Replies 2 Participants Last post by  Scarbelly79
I have a Vortex Viper PST 2.5-10 x 32 FFP on an ADM Delta mount that I've put on my SCAR17S for longer range shooting (prairie dogs, big game, ringing steel at 800-1,000 yards). I like the setup, but I've noticed when I go bunny hunting (smaller fast moving targets from 5-75 yards in sage brush), I have a hard time getting on target quickly due to field of view issues/eye relief, not to mention the ~24 ounces of glass and steel sitting on the rail.

I was thinking of putting a small red dot on a 1 o'clock mount, but I figured it would be better to take advantage of the QD/return to zero features of the ADM Delta mount. I bought an ADM22 mount to go with a Burris Fast Fire III that was sitting on another gun. I plan on swapping over to the Burris FF3/ADM22 combo for bunny hunting and other similar activities.

Now I'm wondering if there are any advantages to mounting the optic closer to the front or the rear of the rail.

I've searched online, and there really aren't any good answers - in fact there are some contradicting assertions of fact. Some experts say the dot gets larger the further away the optic is places from your eye, so keep it closer for more precise aiming or place it further out if you want faster acquisition at closer ranges.

The sight/mount combo is pretty light, so I really don't see the placement affecting the balance of the rifle that much.

Has anyone had any practical experience with this?
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I like my red dots close for quick acquisition. Sitting just beyond my rear BUIS but not so close that I can't easily manipulate and zero the RDS.
Well, I played around a bit with the Burris FF3/AD22 at different points on the rail. Here are my opinions:

-With the rds further out on the rail, it was faster to raise the weapon from the low ready, acquire a sight picture on the target, and pull the trigger, t
han when it was closer to my eyes on the rail.

I think this is in part because the dot is at the same position as my non-firing hand on the fore end of the rifle. Likewise, the frame housing the glass is thin enough to not degrade the FOV, but substantial enough to "frame" the target.

-I didn't notice any significant "blooming" in the dot. At least none that would affect practical accuracy at 300 yards and in.

-Most people with an opinion on this matter are using an AR15 pattern rifle without a monolithic rail, and are placing their rds optics as far forward on the rail as they can without "bridging" the receiver and rail. The stated reason is that they are gaining a greater FOV outside the housing of the reticle.

I'm going to go pop some bunnies tomorrow with the current setup - we'll see how it works.

Regardless, I like the light weight of the micro rds/QD mount. If this works as well as I hope, I can see the possibility of putting a Vortex Razor/Leupold Delta Point/Trijicon RMR on there.

Here's where the RDS is on the rail:
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And here's the Vortex Viper PST 2.5-10 x 32 FFP/AD-Delta mount that I usually have on there:
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