Victors, sending you a PM.. I'm close, and will be in Colorado Springs tomorrow for work... let me know if you'd like a quick eyeball on what you're dealing with, or if you've already got it handled...

I can bring my AR wrench (from Guntech), torque wrench, and my upper vise block... I even have some shims if there are alignment issues with the nut... you'd just have to have a vise.

I'm not a FFL like Bert or Tim- but I have the tools required... you'd do the wrenching, but I'll let you know what to do.
your choice- I won't be be upset if you'd rather use a licensed FFL- but thought I'd offer since I like to wrench my own stuff

Look for my PM in your inbox... I'm finishing up some paperwork on some work I'm doing tonight and will send it.