Anyone have any info on this?

Sure, Clymer has reamers and RCBS has dies. The great 375 Taylor is the 338 necked up to 375 and this is just a case with 6 grs more capacity necked up. You will get 50 to 60 fps more velocity depending on the bullet you select...if you hold to COL 3.38 inches, the 300 grainers will use up your case capacity advantage, because the case is 3.62 long and you need to seat deeply to fit the magazine.

RMiller,
my mentor smith has one of these... on a mauser 98, slim barrel, and a piece of screwbean mesquite that is dark as over boiled tea....

beautiful gun, great round... but, his words, not mine, after I made my 376 steyr, with factory rounds, brass, dies and reamer, he said "I wish that had been out 3 years before"...

since the 375 hh is 95gr h20, and the 300 win is 92, i would expect there to be no reasonable difference in performance or pressure. Just the load data...

the 376 does operate at higher pressure, and can BARELY match "Factory" loads on the 375hh.. i would expect the 375/300 win to match, load for load, the 375 hh...

His rifle does match the 375hh... and that's where he stopped adding more powder... the gun barely weighs 8#, before scope, and he's not particulary a recoil junkie

jeffe