The Hornady 270-300 grain factory ammo is available here in AK (in the MATSU Valley anyway), however not plentiful. I've seen Double Tap and Swift A-frame here just not in 375 Ruger, but if they can get those brands, then ordering what you want here is an option, but may take a while to arrive...
I'm considering getting a Nos 21 in 375 H&H. How is the felt recoil? Did you put a break on it? Are the scope base screws 6x48 or 8x40?
Thanks in advance for any info you can provide.
Hope you have this fixed already and although frustrating, it wasn't expensive. I had a R700 bolt rotation issue years ago - it turned out the action screws were a bit too long or over torqued, creating the binding. A little reduction in their length fixed the problem.