C96 whenever possible as axis, simply because it's cool. Larger clip, but I suspect the inability to reload mid-clip puts it as a disadvantage overall to the P38.
As allies, the nagant revolver always. Sure it has less rounds. Sure it takes an ice age to reload. But it is easily the coolest pistol! And the ability to top off the ammo is handy. Allows you to keep it topped up as a secondary weapon. Though obviously... the reload means you're in for a tough fight trying to depend on it.