Not being argumentative; but you are worried about shooting lower powered, lower pressured round in a carbine designed for much more powerful rounds. That's like taking an SRT Hemi charger in a parade...it far exceeds what you are asking of it. The warning had to concern putting a 375 in a 38-55 I think.
Correct me if I'm wrong, but the 375 was given a smaller bore for just this reason.
In so, a higher pressured 375 bullet going down a .379 ish bore is likely to not cause catastrophic damage. They couldn't build the longer cartridge like a pistol round because of OAL and cycling issues, so it was the next best idea.