I've not shot or handled a SCAR. I have some issues with the design and the recoil impulse is deadly to many optics, so, it's just really expensive. I think there are better options to build an AR10-style rifle chambered in 6.5CM or, I might be pursuaded to buy a Robinson And XCR-M chambered in that, plus you can get quick change barrels for many other calibers.
I hope that's a little bit helpful.