View Full Version : Front BUIS mounting question

06-18-2010, 12:41 PM
I just got my new Sabre defence 24" target upper and I wanted to mount a front sight to the gas block rail. Problem is, the gas block rail is 3/8" or so LOWER than the free float rail (which is flush all the way to the back of the upper). Is there a particular sight made to allow for this lower mounting position?

06-18-2010, 12:51 PM
Yes, there are special sights for mounting on a gas block. Take for example these two sights from MI. This is there standard sight for use on a quad rail:


While this is the same sight designed to go on a gas block:


Special sights that are designed to go on gas block rails will mention that they are designed for gas blocks.

Droppin Deuces
06-18-2010, 12:56 PM
This is the reason I bought an Adams Arms upper. Because the gas block rail is the same height as the receiver. Of course, I bought it with the intention of putting a Magpul sight up there, until someone kindly pointed out that a plastic sight might not hold up so well mounted on that particular part of the gun. D'oh...

06-18-2010, 12:59 PM
That is what I dont like about some uppers... who ever thought about making it like that was just stupid or drinking that day.. lol

06-18-2010, 12:59 PM
I have an Armalite AR10 with the same problem, I am running the MI gas block site and it works very well

06-18-2010, 5:53 PM
Thanks; thought something was awry there! MI it is (until I can afford some nice glass!)