I've got a Ruger Number One in 38-55...really like it...and about all Number Ones. I was doing some reading and learned that the .375 Winchester round was designed sorta like an improved 38-55 to be used in the beefed-up M-94 "Big Bore". I also learned that the two are to be considered the same dimensionally except that the .375 is just a tad shorter. There appear to be numerous warnings about using the .375 round in 38-55 rifles but the reason(s) for this appear to be based on the pressure generated by the .375 over the 38-55. Now...the Number One is a bit stronger than the 94, hence my dumb question...could I use the .375 round from time to time in my .38-55 or is that a bad move?

I definitely have not done so, but am sure thinkin' about it for hunting IF it's safe/practical to do so. Ruger customer service doesn't show any interchangeability in 38-55 and I can understand that.

Thanks in advance and if this post belongs elsewhere my apologies please. Been a member for a while here and, from what I've seen, this looks like 'bout the best place to get an answer to my question. You guys have a neat forum...

The Ruger is a lot stronger than the M94, I don't know about the safety of actually using 375Win ammo in and if it will work, but I load 38-55 brass to 375 Win power levels in my H&R 38-55s with no problems with custom .379" jacketed bullets, 375Win brass is thicker and won't chamber with any bullet big enough to shoot well in it without neck turning the brass, the typical 38-55 uses .377" or bigger bullets, the 375 Win is made for .375" bullets. I've shot .375" bullets in mine and they keyholed at 100yds, surprisingly accurately I might add, but I'm not familiar with the Ruger's bore specs. If you handload, you can certainly get 375Win performance out of a strong 38-55 platform like the Ruger. Paco Kelly uses 38-55 brass in his 375Win Big Bores, whether the reverse will work for you I don't know. The SAAMI website has a list of unsafe rifle/ammo combinations of which the 375 in a 38-55 rifle is listed, but I think that's to warn against using 375 Win ammo in older traditional firearms. The bore and chamber dimensions will likely be the drawback to shooting 375Win ammo in it.

http://fiveshot.org/backissues/paco/375win.htm

Yes, you can shoot 375 Win. in a Ruger #1 without any problem; they both have the same headspace (rim) specs.
With modern 38-55 brass, you can easily duplicate 375 Win, performance and beyond, so that's the route I would take (and have taken with my Ruger in 38-55). Having said that, shooting lower powered loads in the 38-55, especially cast bullet loads, is a lot more fun and economical. Have fun.

i use nothing but 375win brass in my marlin cowboy 38-55 with the 375 hornady 220gr flat point bullet and 30grs rl-7. super accurate(one hole 3 shot groups at 75 yds). to get a good crimp you will need 375 win. dies. a plus is 375 win. brass is easy to find. eastbank.

Appreciate the info, guys. I'll be reloading again soon ( within the year ) and look forward to shooting the 38-55 a lot more then. Probably won't hunt with it this season but, if I do, guess I'll pick up a box of the .375.

Again, thanx for the input!