Hi Tony Parisi,
None of these here-today-gone-tomorrow, "better" .375 cartridges appeal to me (neither does stainless steel for that matter).
However, if a left handed stainless steel rifle in .37 caliber is what you must have, I could see putting up with dodgy ammunition availability and a little more recoil/blast, perhaps a tiny bit more ruined meat and such, from a proprietary cartridge like the Ruger version.
If however you are interested in the Ruger cartridge's potential for higher velocity, you might be amazed at how well you can hit small targets at fairly long range and yet also bag very large / heavy animals at short range with the old H&H.
If you cannot hit something or bag something with the H&H version, buying the "latest & greatest" version from Ruger or any other maker, will not be your salvation either.
Plenty of proper / meaningful practice with your rifle will be your salvation.
I really like the looks and handling characteristics of the rifle you are looking at but, the 23" barrel version would be more to my liking than the stubby 20" barrel would be.
Does / did Ruger make it in 9.3x62 by any chance ?
Certainly the old 9.3 is not a super long range cartridge but I can hit real well out to about 300 yards with 286 grain round nose bullets with mine (Mauser), from the shooting sticks.
Here in Alaska, the 9.3x62 is gaining popularity whereas, the .375 Ruger (and .416 Ruger) seems to be sort of just holding on with a small cadre of loyal fans.
Therefore I wonder if things are the same in Africa for the Ruger version's ammunition availability.
I do like the shape / design of rifle itself though.
And if they have discontinued it, that is a shame.
Sometimes this old world has "wretch rules."
If you see something you really like, you had better wretch out and take it or, it might not be there tomorrow.
If you ever find yourself in Anchorage, with a little time on your hands, let me know, as I only live a short ways to the Airport and I can pop over to say hello, or get lunch, maybe visit a gun store.
Cheerio,
Velo Dog.