I've got a RRA upper coming with the Tactical Carry Handle.  I want to mount a scope w/30mm rings on there but am a little concerned with the fixed front sight will it be in the way?  It's a little hard to estimate scope height from their picture.  Has anyone done this?

Generally, anything over 4x and you won't notice the FSB so height is not an issue as far as FSB is concerned.  With my TA11 all I can see is a slight blur in the bottom of the sight picture.

Get the correct height for your cheekweld and you're good to go.

Good to hear.  

I always figured that as long as I keep it out of the center of the scope I'd be fine but to be honest I wanted a second opinion.  


Now I just have to deal with waiting on RRA's manufacturing lead time

You weren't planning to mount the scope on top of the Tac Carry Handle were you?  That would put it up too high for a good cheek weld and you probably wouldn't be able to get it on anyay.  And the iron sights would be useless.  

that actually is what I was planning on.

I'll have to see how it pans out after I assemble everything.  I'm still waiting on RRA for the upper.

I was able to mount the scope on the tac handle.  The see through rings aren't quite high enough to give full field of view through the iron sights however I don't believe it to be too high.  It certainly can't be any higher than the A2 carry handle scope mounts.  Worst case down the line I'll get a larue or something similar.  

Now what about if I remove the tac handle and install the scope on the top rail of the upper.  Obviously the scope would lose zero but when I stick the tac handle back on would it maintain zero??

I see a lot of QD rings that claim to hold near zero but the only difference between what I have and what they show is a throw lever.  How does that hold near zero better than regular rings I understand the convenience but functionally I can't figure out how it's better.  

I've had pretty good luck switching back and forth between a 2-7x scope and a regular handle on mine.  As a test I shot four 5-shot groups, alternating between the two, and I had a single group at the target at 50yds.  

The rings I have are just some cheap Tascos (similar to these, but higher) that I found at a gun show, but I'm careful to always get them in the same slots, always slide the scope forward in the slots before tightening, and try to keep it about the same tightness.  I think the key on the rings is that the scope-holding part is completely separate from the rail-holding part and that only one side moves in the clamping.   If you can afford it, the Armalite 1-piece mount is good, it has a clamp like the handle, and it has a lug on the bottom to align it in the slot more consistently.  

The only advantage I can think of for throw-levers (aside from speed) is that the clamping force is determined by the cam adjustment, so it'll be the same every time vs. trying to get a nut at the same torque.