I've got a Varminter with a Leupold Vari-XIII Illuminated Mil Dot with a 50mm objective.  Love it.

I'm bent on installing a rear BUIS to accompany my V-Match front sight.

Here's my problem...

I've got exactly 5/10ths" clearance from the first rear slot on the picatinney rail.  It tapers down to 4/10ths" at the far rear end of the picatinney rail.

What BUIS should I be looking for?  Knight's? GGG MAD?  If anyone could take a measurement and share with me I'd greatly appreciate it.  I'd hate to order a BUIS and have it not fit.

Thanks guys.

Hokie:

I'll grab the digi-cam tomorrow and take pictures to show you my KAC 600m.  I did grab the calipers and some quick measurements are below:

Folded down, the KAC600m sits .468" above the rail on my flatop.  The windage knob has a little extra height, coming to a rest at about .55"

Obviously, I'll have to take my scope off (it'' be mounted using an ARMS #19 and #35QD rings) to make use of the 600m, but it looks like it's going to be a nice setup.

Anyways, I'll snap some pics and post them if you need.

Many thanks!!!  I'll owe ya one! [beer]

I figure if the windage knob is offset to either side, the bottom bell of my scope should clear anything above 0.5 inches.  I hope...

It's the folded height of the 'rear-most' end of the BUIS, right near the end of the picatinney rail...I measured again and it's 4/10's...

I might be okay, but I just want to be sure.

Thanks again!

In the Sights & Optics section of the EE, there is a thread from MSTN on BUIS. Half way down on the [url=ar15.com/forums/topic.html?b=7&f=23&t=113106&page=2]second[/url] page, MSTN posts the hieghts of a couple different BUIS.

thanks for the link, that was some good info.  I'm now particularly interested in the folded vertical height off the rail of the Knight's BUIS, and the GG&G MAD.

Hokie:

I think I got some pics you can work with.  I'm not going to post them inline because they are fairly big.  Kind of frustrating trying to get pictures of an all black rifle that shows shadowy details.

[url]http://www.mylittlespark.com/ar15/kac6001.jpg[/url]
[url]http://www.mylittlespark.com/ar15/kac6002.jpg[/url]
[url]http://www.mylittlespark.com/ar15/kac6003.jpg[/url]

Hopefully you can see the small amount of rise that the windage knob it's lip add.  The height of the sight, from the top of the rail to the face with the zero windage markings is .468"  From the top of the rail to the top of the windage knob is .550"   This is the Knights KAC600m. I suspect the 300m would be similarly sized.

Hope this helps.

(Yeah, I know someone will tell me it's on backwards.  But I wanted to push the sight into position, not pull it.  The zero windage markings are facing away from me, but the windage knob is on my strong side which I am most likely to use.)

AWESOME.  I'm going to order a Knight's 300m.  The pics did help alot also - thanks.  I appreciate all your effort.

Cheers YB