I like the Mosin Nagant alot, good, stable fire, the loading is a pain, as I have shot one myself, in fact, I own one. I like the Potatoe masher grenade as well.
But my utter most favorite, is the Sten.
Not only was it extremely cheap, It was easy to use, it had low recoil, you could modify it in numerous ways, such as a longer barrel, a bigger magazine, Or a folding stock, better ring hammer for punctaul firing rate, and diffrent sights and such.
It was also light, compact, and didn't jam or break easy. Not only that, you could weatherproof the Sten by coating it in special varnishes to prevent it getting soaked or getting sand stuck in it. Not only that, the Sten's ammo was very easy to find. the ammo was very common, and Plus, the sten could be fitted, as long as you modified the barrel's strength and length, with a Bayonet. Which is extremely useful, considering it could be used as a tool.
the British Sten is my favorite gun in world war 2. The russian PPSH isn't bad eitheir, due to it's loading mechanism's with the catridges allowing quick insertion and withdrawal. The only thing I find bad about the PPSH, is that it's accuracy isn't the best. It's better for swipe and clear operations, such as tommy shooting a room to clear it.
A sten o nthe other hand, could be used for banding shooting where you strafe the gun to deal massive barrages. And with its quick reloading, and modifcations for improving accuracy, you have a mean gun.