I've cut some shouldered barrels on 3 of them, 2-6.5CM, 1-6CM.
1 went into a KRG Whiskey-3, 1 in a KRG X-Ray, 1 in a MPA. All running Timney Triggers. Proof, Criterion, and X-Caliber barrels on them.
Really just pick the flavor you like and run with it, so far liking the actions.