Okay, H. Wally, time to be honest (I can do that when pressed, you know!): I have no first-hand knowledge whatsoever of the K-31.
However, I do know a bit about the old 1889-based actions, currently having a couple in 7.5 and another in .30-30. All, of course, have 3-groove barrels with wide grooves and fairly-wide lands. The original '89 action was l o o o o o n g and it was heavy and it was rear-locking. Those two massive locking-lugs were almost the size of a John Deere tractor and they were machined pretty much to the proverbial "Swiss-watch" standards of perfection.
With that length, the actions should have been springy, but they also were massive enough to counter some of this springiness. And they were accurate, too. When I am shooting an 1897 iron-sight military rifle and it is performing almost like a new scoped sporter, I say there is nothing basically wrong with the thing.
Over the years, the action got shorter as redesign followed redesign. The locking-lugs migrated from the back end of the locking-sleeve to the front and, on the final version, that long bolt-shank finally disappeared and left the locking-lugs, just as massive and beautifully-made as ever, locking-up RIGHT behind the chamber. So you ended up with a truly massive, very short action with an incredibly-strong lockup, right behind the cartridge. This is almost a recipe for accuracy all by itself; the Ross is similar. The Swiss added to this by keeping the action very solid and with a lot of meat on its bones. Check out the latest bench-rest actions and you can see much of this in them. The Swiss put it into an Army rifle.
Now here is a point: that old '89 action was springy just on account of its great length. The '96 was he first improvement, the 1911 the second and the '31 the third and last. Each one was less springy than the one before, which normally means more potential accuracy from the design of the RIFLE.
Now you look at the ammunition. The cartridge was designed by Major Rubin, who also was responsible for the major part of the design of another fine old long-range cartridge: the .303. The two rounds share a lot more than a designer; they also share a lot of characteristics, characteristics which fit them eminently for accurate shooting. Both are, by present standards, too large for their performance; by no standard can you possibly call either one "high intensity". Indeed, the Cordite loadings of the .303 were considerably UNDER the pressure of the BLACK POWDER loading. The TEXT BOOK OF SMALL ARMS - 1909 gives the following chamber pressures:
.303 Mark VI: 15.5 ILT
7.5 Swiss: 17.1 ILT
7.65 Turkish: 19.7 ILT
.30M-1906: 19.78 ILT
7x57 Spanish: 22.3 ILT
3-line Russian (214 bullet): 17.47 ILT
7.9 German (227 bullet): 21 ILT
7.92 German (154 S type): 17.5 ILT
In each case, ILT stands for Imperial Long Tons of pressure, per square inch. 1 ILT = 2240 lbs.
And we find a few anomalies. The superbly-accurate 7x57 had a built-in pressure handicap which was cured by the comparatively heavy barrels of the rifles. The low-pressure 154-grain S-load of the German rifle was never regarded as much of a long-range cartridge but, at shorter ranges, it shone. It was handicapped by the high base-drag of the S bullet. I have tested original bullets with powder duplicating the original, and the 100-yard performance was quite amazing.
The .303, in 1910, came out at 18.5 ILT with the 174-grain Mark VII bullet. This was NOT the most accurate loading possible; it was about 10% (in velocity) higher than the by-test most accurate load which the Royal Laboratories had been able to build, or close to 20% higher in pressure. Drop the .303 by about 10% in velocity and you WILL be amazed at what your groups look like. But Britain regularly used rifle-fire at much greater ranges than most other countries (partly for lack of expensive machine-guns) and the Army was trained to the highest standards of any world-class military. They took the extra range made possible by the new ammunition and made up for its small shortcomings with superb training and rapid fire.
The Swiss, on the other hand, stayed with their BIG, old casing which allowed them to KEEP their pressures low.... and enjoyed the advantages which it gave them.
And here I digress, possibly. I spent 25 years shooting with a very good friend who reloaded ALL of his ammunition... and did not even own a powder measure. Gavin Tait used a cat-food tin, a silver spoon and a tiny bit of creased paper; with those, and his RCBS 505, he loaded some of the most accurate ammunition ever seen in this part of the world. He hunted for the pot because he spent most of his life needing to hunt for the pot. And he was almost completely colour-blind: he HAD to make a 1-shot kill because he could not track a wounded animal without seeing it. And he regarded wounding an animal as a sin against the God Who had created it. Add these factors together and you had a man who could see a deer at 760 yards, fire his single round and go and get the pickup truck to load the deer aboard, secure in the knowledge that the animal had not even known that it was in danger.
His recipe for success was simple: keep your rifle clean and your screws, ALL of them, tight. Hunting season lasts ONE round, so you practise, Practise, PRACTISE until you KNOW that you can put that ONE round precisely where you want it to go. And you load the most CONSISTENT ammunition it is possible to load.
And there is wisdom in that last sentence. We loaded many loads for a lot of rifles in 25 years and the one thing which stuck out, plain as paint, was this: CONSISTENCY in your ammunition is FAR more important than having a "pet load". The British got consistency in their loading by staying with Cordite; the Swiss got consistency by tightening-up tolerances all along the line and in every department.
The rifle barrel and action twist about and sometimes compress and always vibrate with every single shot. If you can keep the rifle vibrating and twisting about in PRECISELY the same manner with every shot, the bullets SHOULD all go to the same place. You get this precisely-the-same vibration pattern by making your ammunition CONSISTENT and you minimise the motion by keeping your pressures low. Cases must be the same weight, therefore volume, primers must be the same and seated the same, powder must be the same charge to a 1/20 of a grain, slugs must all be out of the same box or, at very least, the same Lot number, seating must be the same..... and the bullets should be seated just a hair from touching the lands. And you keep your pressures reasonable; the American infatuation with 65,000psi loads and even hotter is a recipe for inconsistent vibration patterns, bullet-stripping and just about any other horrid thing you might think on.
Put ammunition made to THOSE standards through a solid rifle with an action like a bank-vault (which includes Schmitt-Rubins, especially the K-31..... and it includes Rosses as well) and you HAVE to get results.
I apologise for the sermon, but it is hard to put 25 years of experimenting onto a keyboard, and do it in less than 40 hours, without a bit of sermonising!
Hope this helps.
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