I’d strongly recommend the Leica R’s.
Both my son’s have them and we’ve been impressed.
I’m still using my 9 year old Geovid HD-R’s….they’ve been stellar.
I ‘d buy from from Doug @ Cameraland.
I've mainly built on pre 64 Model 70's and have had great results with folks that know that action.
If you're wanting to build on a Tikka or Rem 700 Clone I think the list gets even longer.
PM me if you're looking for suggestions for a model 70 or Kimber.
Almost all my model’s 70’s have FWT barrels either factory or aftermarket, they all shoot good enough for my needs.
Another barrel I’ve used with great results is a Lilja #2.
I’ve had several generations of both swaro and Leica with onboard ballistics but not being a long range hunter (500 yards and in) I settled for the the simpler tool and have been very satisfied with my Geovids.
My sons both have the newest Geovid R’a and have been very pleased with them.
With...
I just finished putting together a few customs based on kimber 84M's that turned out well , topped with NXS 2.5-10x42's the 6 CM is at 6 .75 lbs and the 6.5 CM is 7.25, both have 22" proof CF barrels.
I wouldn't want them any lighter.