Thanks for the model clarification.
IMO: As for bedding, I would skip the allthread. Unless it is perfectly bedded {and in epoxy to-boot} the chances are you will weaken the stock, not strengthen it.
Ruger normally does a good job of selecting stock layout that runs the grain properly thru the wrist.
The front recoil lug arrangement does complicate matters a bit and IMO probably introduces tolerance in that area that could lead to setback into the tang. That whole recoil strap affair has never impressed me very much but it would only add a little time and taping off to isolate the bearing points for bedding compound.
On the standard 77's, I bed the whole "box" and allow it to level off just a bit over the shoulder and freefloat the barrel. Rugers are one of the easiest rifles to epoxy bed...and also are one of the most responsive guns to it of those I've ever worked with.
If you have concerns with the stock cracking it is easy to lay a small bolt in a trough cut in the recoil shoulder side-to-side. Unnecessary probably with a Ruger stock and the .375 unless...
As for the caliber, my own personal .375 {Sako} has seen several thousands of rounds. The .375 {Ruger or H&H} has some recoil but is not a stock wrecker if the gun is bedded anything like appropriately. I rebedded mine after 20 years a few years ago after I got some problems with forestock contact {eventual warpage} when I had it reblued. This is a gun that has seen a lot of hard use and after a hunt or two has even been held by the sling and had a garden hose turned on it...
Many Ruger 77's are poorly bedded and as stated, I have no experience with the recoil strap thing but it is not a particularly confidence-inspiring feature of the rifle {because it would require really superb fitting to add strength, and Ruger is great at a number of things, but close wood/metal fitting is not normally on that list...}. Personally, I'd check the gun out closely and bed accordingly.
I'd bed the recoil shoulder and add a dab at the tang as I always do with all Rugers regardless of caliber. I wrap the rear of the tang in tape for clearance, or just bed it snug and then relieve with a dowel wrapped in sandpaper and yes, I'd for sure relieve the tang.
I would also bevel the ejector slot edges in the bolt head and bevel the ejector sides/edges. Takes less than a minute to do. On violent, fast operation, the Ruger has been known, and I have experienced it myself, to jam as a result of the relatively weak ejector spring not forcing the ejector up fast enough to strike the cartridge head when the bolt is in the most rearward position after hard, fast bolt operation. IMO Ruger needs to include a heavier ejector spring but there are commonly burrs on the edges that need removal anyhow.
Anyway, the bevelling has solved the problems for me entirely, tho the spring tension is noticeable less stiff than CZ's that have a similar action type.
