I have personally witnessed 8x57 mauser cartridges being fired through 30-06 chambered rifles by people that should know better, with no visible affect or damage to the rifle. Likely because of the very generous ''freebore'' condition.
Look up PO Ackley's experiments on trying to blow up different bolt action receivers. PO did tests on just about every known and easily obtainable bolt action receiver to personally verify at what pressure levels they would fail or cease to be functional.
The strongest action he could find at the time was the M38, Japanese Arisaka, chambered for the 6.5x51 Jap.
No matter which powder he used in the cartridges, he couldn't get the Arisaka receiver to KaBoom.
So he decided that he would recut the chamber using a 30-06 reamer and leave the bore 6.5mm
Starting with a standard load, generating 47000 psi, with 150 grain bullets, he fired several rounds through the rifle, with no visible damage or malfunction. The bullet just swaged down to the diameter of the bore and went on its merry way down range.
He became quite frustrated with this as the experiment continued well beyond what should have been a safe range of pressures into KaBoom territory.
Finally, he used a 200 grain bullet, over a compressed charge of the 2400 Alliant powder available at the time and finally got some destructive results.
Even then, after having to remove the barrel to be able to open the bolt, as the brass had flowed around the lugs during firing and siezed things up, the receiver and bolt were undamaged and were eventually used for a rifle build.
The Arisaka was the only receiver this happened with. None of the others even approached this strength or durability level.
Back in the day, when money was tight and components were often difficult to access or even get shipped to the small town I lived in, I loaded up and used bullets anywhere from .3075 to .323 diameter in my 30-06 rifle (P17 Enfield) with a mid range load from the Lyman and Hornady manuals, printed in 1967, without any noticeable issues.
The only reason I didn't get to use larger diameter bullets, is they wouldn't fit in the chamber.
No, I'm not advocating that anyone do this with any of the firearms they have on hand, no matter how desperate.
I'm just giving you my personal experience in a rifle that PO Ackley proved during his destruction testing, wasn't any stronger than any of its counterparts at the time, even though popular opinion said it was.
I knew an old Elk hunter, living on a ranch just outside of a small city in British Columbia, called Cranbrook, that bought a P17 when they were being sold off for $5, new in grease, along with a crate of surplus 7.92x57 ammo made by Winchester for the Besa machine guns.
He used that rifle, with that ammunition for over 50 years, to shoot the Elk that were ripping up his haystacks and raising hell in his back yard, between the barn and the house. None of his shots were over 50 yards, and all were in the boiler room.
I would guess he was very careful of where he took those Elk, because the FMJ bullets would just keep right on going after passing through the animal.
He complained about the recoil to me, so I loaded up a few hundred 180 grain, round nose bullets, to a very sedate 2400fps and they shot within a inch or so of POA with the original iron sights on the rifle at the distances he was likely to shoot.
He shot a couple of those rounds and went back to the surplus 8x57 he still had left.
Well, he's gone now to his rest and I cleaned up that rifle for his Grand Daughter, who he was very close to. It resides in the safe and will likely never see the light of day again, but it's still very serviceable.
