Bolster, what kind of panels do you have on your DD?

Quoted: Thanks joseph.  That kind of what I was talking about.  The fact that even thought the holes may be aligned close enought to allow the gas tube through, the rail might not be true to the rail on the upper.  It kind of sounds like it is a trial and error/pain in the ass process.

You've got a big advantage... you KNOW about it.  The first DD rail I put on, I didn't know to check, so I put it all back together, shouldered the weapon, and noticed the forend rail didn't quite line up with the flat-top.  So I took it back apart, but afterward, I'd just adjust the nut, thread on the forend, check alignment, unscrew forend, nudge barrel nut, re-attach forend, etc.  I think it took 3 or 4 tweaks to get it right.  

Funny thing is though, the next two DD forends I did were straight on the first try.  I was so amazed, I apparently put one of my gas tubes in UPSIDE DOWN and ended up with a single shot rifle at the "test firing" session!

I like my DD, and though I'm positive the LaRue is a great product, I just haven't felt any need to switch.

There is enough play in the LaRue locking system that it also requires trial and error to line up the top rails.

Quoted: There is enough play in the LaRue locking system that it also requires trial and error to line up the top rails.

yep.

Good to know gentleman, thanks.  I think I'm going to install the DD.  If I really don't like it, I'll get a Laure and save the DD for a truck gun project I have in mind......