I just finished a 35 Whelen on a 1903 Springfield. I inherited a 1903 that had been sporterized in the 1950s. A local mechanic, machinist, gunsmith turned the barrel down and soldered the bolt. The late owners wife finished the fajen stock, it was a legend in our little town. By the time I got it years of shooting tracers on the 4th of July burned most of the rifling out of it. Not wanting to lose the look of it I sent it Jess @ JES Reboring and he made it a 35 Whelen. The stock was split from the tang up through the mag well so I used devcon and brass rods to put it back together. I also have a 338-06 on a Mauser X, that was a new barrel, not a rebore. If dies were easier to find I would have done a 375 Whelen.
I hope the video plays. As things worked out I bought hundreds of 250 gr Hornady, Speer and Norma Bullets. They are all over twenty years old, still clean and in the original boxes. Having read online that old 35 caliber bullets are likely to suffer from the lead corroding I just had to see if they would in fact grenade. At a range of 10' they penetrated all but the last few water jugs. The hydrostatic shock broke the 2x8 they were on and the bulleted exited without hitting the last few jugs. This is very similar to what my 338 WIn Mag with 250 Partitions does. Not super scientific, but it proves that affordable projectiles work great at Whelen velocities. The video is slo-mo, it might not run. Just trying to make a happy distraction.
The Whelen likes 4064 and I can make it from '06 Brass. Not sure how easy it is to make or feed 375 Ruger. Here in upstate NY the only powder that I have been able to get recently is 4064 and 3031. Lucky for me the Whelen likes the old reliables. The downside of what I did is the Springfield is heavy! That does help with recoil. (Elmer Keith never complained about the weight of his 1903 Whelen.) When the weather improves I wil cast some 310 gr flat nose projectiles, it shoots the 250s so well I should not have bought a mold!
Sorry I wrote so much, just like the Whelen!