I've been through nearly 100 barrels this year, Proof, Kreiger, Rock Creek, Bartlien, Brux, Broughton, XCalibur, Hart, Lilja and Benchmark. I've only rejected XCalibur, most smiths I'm convinced don't even check barrels or don't really care, I've slugged every one that I've had and I have never had one as good as the worst of any other barrel I've used. Some friends went through two 375 barrels that were so far out of spec it was shocking, they ordered a 375 barrel from Rock Creek and it was dead nuts to the spec.
I'm a Montana gunsmith and I like to use our Montana products and I'm price consience but I will not use one of those barrels on a build and compromise the quality of the heart of a precision rifle, even the one barrel that I have used that was technically in spec I'm afraid will have issues down the road because of inconsistent heat treating which some are reporting. Another warning is how many stories are out there of barrels being bought back!!