I already have an 762-SDN-6, which is also why I'm leaning towards the 9" AAC upper.
Have a 556-SD for the 5.56 uppers going into jail (well, as soon as the damn form4 gets mailed).
I submitted one earlier 5.56 7.5", just kicking the can on the other right now. I'm just itching to get two more lowers SBR so I have something new to diddle with. As if I have time to go the the range anyway...