Handguns - I'd go for a pair of S&W 1917 revolvers with plenty of extra ammo in ½ moon clips. (full moon clips didn't come out until the 1980s and back then the 1911 sights were just too small.)
Shotgun - 1901 Winchester lever action 10 gauge sawed back to the magazine. (back then the 10 beat the 12 hands down) Hmmmm did they make a 10 gauge Poly-Choke?
Rifle - 1917 Enfield (the magazine holds six as opposed to the Springfield's five and ya gotta love that rear sight!)
Subgun - 1921 Thompson with the infamous C-Drum. (the 1927 is semi only and there were very few 1928s until the late 1930s and they didn't like the 100 rd C-Drum) with plenty of stick mags for back up (changing out a drum is SLOW)
Heavy stuff - Colt Monitor (commercial version of the BAR) with plenty of tracer & AP ammo.
Hide out guns - S&W 1913 in .35 S&W (yes .35) or a Remington Model 51 or Colt 1903/1908.
Yes it's all a big dream.
But dreams and what-ifs can be fun.
But the biggest dream in this entire thread was from the person who mentioned carrying an N-Frame S&W in an ankle holster!
You'd have to have ankles bigger than Rosie O'Doughnut!