Originally Posted by
JSantoro
They are extremely able to take hard use.
That said, there is one thing that should be checked upon receipt, and looked for as the thing is used.
-Mount it.
-Flip it form stowed to UP, and back a few times.
-Observe the windage knob to see if it turns when flipping the thing in either direction.
It's not common, but I've seen it happen on 4 sights out of a new batch of 100, and sporadically in other batches (I don't know in what count batches the original receiver gets them; the ones I saw had been re-packaged and were in 100-count batches). I have one that does that on my Noveske upper, but the one on my BCM upper does not. Being uncommon is not the same as not being potentially undesirable, so check it out.
Personally, I don't care, as I take the "BU" part of "BUIS" seriously (if I flip it up to use because oh-shit-my-RDS-is-down, I would have to be idiotically preoccupied by such minutae to worry about it being off by 1 click of windage), but for those who DO care, it's the only thing on that baby that I could concievably be called a no-go.
It's certainly worthy of rogering up to the vendor, if present.