AR BUIS question

[BUmmedic]

Okay... I've searched the interwebs and and seen many opinions, some taking it seriously and some not so much, but I've got a Spikes Tactical AR build with a Burris 3x magnified optic mounted on a one-piece. Due to the eye relief, I have the optic mounted as far back on my upper as possible. This ruins any chances of mounting a rear BUIS behind the optic. I am thinking of mounting 45-degree sights (I know, there are varying opinions of these, but I figure if I'm using them, it's either as a last resort, or I'm transitioning from distance to CQC/short-range shooting). My big question is, and is know I'll be giving up on sight radius, what's everyone's opinion on mounting the rear sight in front of the optic mount? I've heard all and seen pictures of this configuration, so it can't be completely out of the question. Thanks in advance.

 

[bofh]

If this is a fixed 3x optic then putting anything in front of it doesn't make much sense. If this is a magnifier sight for red dots with a fold-away mount, like the Burris AR-Tripler, then putting backup sights in front of the entire sight combo is the way to go. The sight radius is either the same or slightly larger than 45-degree sights and they would be co-witnessed.

 

[bofh]

FYI: The standard setup for red dot magnifiers with a swing-away mount that is accommodating backup sight is this:

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[BUmmedic]

It's an AR332 Burris fixed 3x optic that is mounted fully rearward. Thinking of a 45-degree rear sight just in front of the one-piece mount. Here's a pic of the current setup:
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[bofh]

Yes, this calls for a 45-degree BUIS. Now, if you can, mount the scope just one slot further forward to get the BUIS rear mounted behind the scope. If this is not possible, in front of the ejection port is the first possible option. The reduction in sight radius doesn't matter if you are only thinking about using the BUIS for short-range targets.

 

[BUmmedic]

Thanks much for your input... I'll try as you said. Got this AR in trade, built by a retired Army armorer, and it came with the optic, so just trying to work around it.