A good friend of mine has a 7prc on an ace blank, shoots really well! I have a few 6.5 blanks that will be cut to 65cm for my nrl hunter build. They offer a lot of options in 6mm: 237 bore and 236, 6 and 4 groove. I need to call and pin down some info prior to ordering a 6mm blank but I will be eventually.
Edit: forgot to mention I have an ace rem varm 9tw 30cal that getting chambered to 300norma imp at 22" on a bat igniter, that's going in a manners pro hunter for a long range elk rig.