After the optic and riser showed up two days ago, i first installed with the riser and added a sig romeo 5 with low mount to the top for initial fitment.

I threw on the ballistic helmet with earpro and nods and gave it a test.

At 70mm, the magnified optic is just a hair too high for comfort. No issues with the helmet mounted Sordins. RDS seemed ok. No issues with passive aiming.

I then removed the riser and went stock 60mm height and everything just fell into place.  

I could get down comfortably behind the magnified optic with a very solid cheek weld and the RDS just snapped right up to NOD height.  

I removed, added blue locktite, and reassembled.

Much impressed with the set up, although the overall height of the gun with optic means it can only travel in very specific gun cases.

AUG with SF 3x and Sig R5

Thanks for the quick impressions.

Nice. The 60mm height works for me as well.