For whatever reason, on the newest version of the mod, the trenchgun will now pump twice when reloading from empty. Before, best I recall, the protagonist would load one shell, pump to cycle the new round in, and then load the other five. Now, he does all that, then pumps again when finished, immediately visually ejecting what should be a live round. What's up with that?

Aside from that, no real complaints. 

Ignore everything below. Just gun nerdery about something that is FINE and doesn't need to be addressed.

The Model 10 realistically shouldn't be vastly out-damaging the bigger, stronger .45 ACP with its .38 Special, but I checked around for other big bore revolvers of the time. Your best bet would probably be something chambered in .45 Long Colt, so either a Colt Single-Action Army (the classic cowboy gun) or maybe a Colt New Service if you want double-action? .38 Special is generally loved for being accurate and easy to use, easier even than 9mm. .45 Long Colt is still roughly in the same ballpark as .45 Auto, though.

Were I to suggest a gun I could perform as well as our hero's "Model 10," I'd probably START with .44 Magnum... but even .357 Magnum was made in 1935. .44 Magnum, is from 1957. This mod is set in the 1920s. 

...So... IDK. Something about that Model 10 is magic. That's the best I've got. Nothing wrong with a kickass, magical revolver that can fan its double-action hammer somehow.