[I have read that Winchester made some '94's with "fat sides"..for strength in some big bore offerings i.e. 444. Does the '94 in 375 Win have the 'fat side' action ?]
All Big Bore 94's Winchesters, including the top-eject .375 (BB94), and the later angle-eject's (BB94AE) in .307 Win, .356 Win, .375 Win, .444 Marlin, & .450 Marlin, had the rear third of their receiver sidewalls thickened outward/bulged for extra strength.
The "extra strength" was for the difference between the Big Bore loads and the previous standard levergun loads, like the .30-30, .32 Special, .32-40, & 7-30 Waters.
AFAIK, the respective pressure tolerances for a BB94 & a Marlin 336/1895 is very similar - neither suitable for 50,000psi.
IMHO, a 50,000psi custom levergun is BLR territory.
BTW - FWIW, Those BB94's factory prepped on the receiver side for a peep sight require a dedicated peep, due to the bulge not letting standard M94 peep sights fit properly.
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