Looks like most folks have them mounted about the middle of the rail.
The reason I ask is that I have a new LaRue FUG which I'm going to stick on my Colt 6940.
Thanks for your replies.
Thank you very much sgwlower ! That's exactly what I needed to know.
As far forward as possible...
It varies depending on the weight of that particular rifle. Usually to the forward 1/3 of the rifle, then evaluate with some range time.
This is where I put my FUG and it works for me,but I'm a fairly big dude, so if I put it in closer I'm to scrunched up to be comfortable.
Edit- Colt 6920 with DD rail
Thanks very much for all your responses gentlemen. They're greatly appreciated.
Got the FUG mounted in a comfortable position. If it wasn't raining cats and dogs, I'd be at the range right now.