I'd go with a short, lighter contour stainless barrel, in a XLR magnesium or aluminum chassis, a light weight scope and rings, personally I am not a fan of carbon fiber barrels and would look at other ways to save weight if I was to build a light-er comp rifle.
We have built a few on MullerWorks barrels, shot very accurate and lightweight, we are currently waiting on some 1.250 strait carbon fiber barrels to chamber and test.
While I’ve read mixed reviews, I have shot with 2 folks running the Christensen Arms Ranger. The one fella swears by his for bench and squirrel, the other gent shot his several times in our monthly MARS events. He came in second twice against a field of big name equipment and shooters. At 5.1lbs you could do worse. Only caveat is prices seem to be all over the place for the exact same model, so shop carefully.
It's a cool stock and I really like the butt stock and all the adjustments but the forend is pretty tall for PRS matches. I've had it for a few years and I haven't had a single issue with it. I also really like how it comes apart with the push button.
