Hello: I just got a box of .375 Ruger Ammo to satisfy my curiosity...I was dissed before by stating the case was mostly a .35 Newton base...
however, on careful miking of the .375 Ruger...I get 0.329" not the claimed 0.332". The original
Newton case I have mikes 0.328'. That's 1/1000th
difference is all.That's total diameter difference.
Head diameter. However, partly right, partly wrong..the diameter at the shoulder is slightly more on the Ruger compared to the Newton:
I get 0.512" of the Ruger, and 0.510" of the Newton (.30 Newton). That's .002" diff. quite small still. But the big difference is the length to shoulder, which is 2.02" of the Newton, whereas I get 2.18" on the Ruger...so the .375 Ruger shoulder is quite a bit further forward...0.16", nearly 3/16"! The the .375 Ruger case itself is 2.572", and the Newton is
2.50"...or .072 inch longer, or a little over 1/16" longer case.
Still, nicely similar so that I can run the .375 Ruger through my .35 Newton or .416 Newton dies & get a .35 Newton or .416 Newton. (have to trim total length, though.)
I can still use the .375 Ruger Brass to get my Newton unbelted brass...Thanks, Ruger!
Best Regards,
Tom

awesome news for newtonites!

the 35 newton just got a new lease on life.

and headstamped brass too for travel!