I have a 1903A3 (Remington) bolt and receiver on the way and to be delivered tomorrow (Monday). I am quite perplexed at the cartridge choices available to me. I know the original is the 30-03 which evolved a bit into the 30-06. The problem is that romantic .473 case head just jumbled my brain. I'm not going to call this project "sporterized", since I'm starting with a stripped receiver and bolt. This will likely not be built as a period correct rifle, but won't be decorated with tactical trash.
Of all the .473 head family, these ones interest me the most. I don't want to go any smaller than .30 caliber but just can't decide about .30 or .35. This will be a cast boolit rifle with everything done with that in mind. This rifle will be shot frequently and treated as a tool should. I need some help deciding which direction to go.
I have my (self-imposed) choice of .308, .30-06, .358 Win or 35 Whelen. Between the 30s, it's about dead even. The 30-06 will be better with 200gr+ boolits I imagine with the slightly longer neck. The 308 has cheaper brass and NATO brass is available (primer crimp is no issue for me). With the smaller charges of cast loads it makes it seem more efficient than the 30-06. I think in the 30 caliber, I might go up to 190-200gr, but not over. That makes the longer neck of the 30-06 a non-issue.
Between the 35s it's a bit more involved. Brass is basically the same as the 30s and I plan on forming it using the 30 caliber parent case if I choose to go with either 35 caliber cartridge. It just differs in cost. Longer boolits in the Whelen would allow me to tinker with 265+ boolits and still get them up to speed over the WCF. The longer cartridges in either caliber would allow for heavier boolits over their short action cousins.
The bulk of my shooting will most likely be with lighter and medium weight boolits, like the 130-160gr range. In the 30s I would shoot a 311041 and the 35s would find a .35 caliber version of similar design as the workhorse. I'm not sure how much practical shooting I will be doing with heavy boolits really. That could change though. Other than component support, a new barrel could cure a bad choice.
My rifle experience is on either side of the spectrum in 30-35 territory. 375 H&H up to the 45/70 and mostly 223/5.56 with a short affair with the 7mm-08. This is very new for me.
I guess that's a really long way of trying to figure out if the 1903A3 action has any issues with short action cartridges. If it does, that will dictate the choice be between the Springfield and the Whelen. If there isn't any issue, then the NATO and WCF will duke it out.