You should call/email Speedy Gonzales, Benchrest Hall of Fame Member, and ask his opinion on the Grendel.
www.sgyrifles.com or speedygonzales@sgyrifles.com
He does have a Grendel reamer and could fix you right up.
It is a fabulous solution to what you are looking for, and it is not going anywhere but up. Alexander Arms is currently producing 200+ AR uppers per month, and several big name mfgs are going to announce Grendel offerings at Shot 2006. Lapua is committed to making the brass and it is available in significant quantities. Can't beat Lapua quality native brass as well, no necking up etc...
Frr your intended purposes, the Grendel would be a great round. Out of the 8 twist you can shoot anything between 85 grain Sierra HPs to 130 grain Normal VLDs. Options!!! My original barrel, and out of the AR platform, I routinely got .4" groups at 200 yards with Sierra 120s.
Visit www.65Grendel.com and you can read much more about the cartridge there. There is also a Gun of the Week article here, Week 27, http://www.6mmbr.com/gunweek027.html discussing the Grendel.
Here are last groups I shot with my BR Rig,Panda action like yours) in the Grendel:
That 5 shot group is at 200 yards, subtract out the .264 and you can see the potential.