Interesting, Steve. I had my first .375 H&H in about 1973- age 23. I had a .358 Norma Mag. at age 21, pulled the barrel and put on the 602 .375 I paid $100.00 for, unfired. My .358 bl. came off and the .375 screwed right one, sights straight up and down, headspace perfect or close enough.
Like a fool, sold it so I could build a .308 match rifle. did well, with that, though. 1st Unclassified then 1st Master in two Cross Canada Matches.