Just a list of what guns I upgraded. Hope this helps you to what not to upgrade and what to. I can't remember all of the weapon upgrade names.
Colt-45 = a 8 round hand held rocket launcher Kars98k = Armagedon = Just more powerful rifle and ammo capacity G43 = G111 Compressor = More powerful rifle Thompson = More powerful and more ammo cap Mp40 = Afterburner = More power higher ammo cap Trench gun = more power higher ammo cap double barrel shotgun = 24gauge longrange = more power further zoom in smaller grouping of pellets Type 100 = Untested Magnum = Just stronger PPSH41 = The reaper = more power higher ammo cap BAR = untested M1 carbine = Untested M1 garandw/Grenadelauncher =The imploder = higher power higher Grenade count, Grenade has a magazine of 3 rounds per clip (you have 3 rounds per grenade per load instead of one) STG43= Spats 447+ = more power higher ammo cap MG42 = Baracuda = More power higher ammo cap Browning 1919 = Accelerator = more power higher cap FlameThrower = FIW nitrogen cooled = slightly lighter longer PanzerShrek = Untested PTRS41 =untested Laser pistol = Porters x2 laser gun = more power higher ammo cap Wanderwaffe = more range on zappyness and higher ammo cap
Right now I can't remember all the weapons. If you tested the guns I didn't test out yet please share :P.
Thanks Boxer for the info on the Bar, By the way, the guns I think that are the most useful is the Colt, M1garand, mg42, browning , ppsh41, ray gun, wanderwaffe , shotguns, and STG(only reason so far is on how far it is at the Bunker, If ammo is really needed you can purchase more lol.)
ya the PaP trench gun is beast. and it looks so sexy. the bar was suprisingly effective too. oh and the type 100 upgraded turns into the 1001 samurai. it holds more ammo and does more dmg. i think it might have a faster ROF too but im not sure.
panzershrek i cant remember the name but it gets 3 rockets per reload so you can shoot 3 rockets fast without reloading (like the grenade launcher), you can run faster with it, and it seemed like it had reduced splash damage