is to fire regular 30-30 out of it, blows the brass out to the .375 chamber for re-loading. You can do it to fired brass if it's not too aged by making blanks with fast pistol powder up to the neck and tissue plug so you don't spill it. If brass is too hold it may split at the neck but won't hurt anything but the brass.
The .375 is sort of a high pressure version of the old .38-55 Winchester that actually calls for a .377" bullet from the transitional period from black to smokless powder. The .375 Win. is a true .375 cal. but I have fired .377 cast bullets fine. Lee makes a copy of the old Lyman .38-55 bullet at 265 grs., good for about 1800 fps. I cut down a mould and made it into a gas checked version at 215 grs. It really sails with my loads and H322, about 2200 fps! It's a step ahead of the .30-30 for sure but no .45-70. But it shoots flatter too. A pretty versatile idea off the old 1894 platform. The original .375's had no provisions for scoping, which I never lamented. I think they have drilled and tapped holes for a receiver sight that is plenty good to 200 yds. or more. That's what I want to install.
I would love to convert it to .400 GNR for fun and I know Puffy would give it a thumbs up. But collector value and practicality compared to stuff I already own stop me every time I get the itch. In my view it was/is the pinnacle of the M1894 evolution. I know Win. did the 7X30, .307, .358,.444 all on this platform too but those were a bit wild and not true to the spirit in my view.
The BB94 has no safety buttons, no angle eject, and is pure to form. Beautiful blue, nice checkering on real walnut, I can forgive the tinny, re-worked post-64, action even. Beefed up at the bolt-lock area and souped up within reason, I like that. Hornady used to make a 230 gr. JSP bullet I really liked, H322 is a grand powder for it too. I think they are worth $600-900 or so now for a really slick example. Puffy needed some cash for something and I think I gave him $500 or so for it, fixed a swivel hole in the buttstock (can't see it at all). Lighter and handier than the Marlins to me, I see them as superior true "saddle guns". Even admitting the obvious shortcomings by comparison. I'm sentimental.