people in the past(2015) worked on weapons
link to original post
https://gtm.steamproxy.vip/app/310890/discussions/0/535150948603799920/
other than that, I would use some conversations between developer and them without references(no MLA format and I hate essays)

me
work on other stuff, add some missing weapons, fix some errors
I'm not a superman and too lazy to go over this dead game over and over again for collecting all stuff(only 1 completed round)

you
I might be wrong and miss some stuff, so it is your responsibility to help me by leaving a comment

from crates(loot(weapon, attachment, scrap), explosives and medical)
currently don't respawn(future update would do that but as we know the developer has disappeared)

I've collected all the crates, so how can I get new crates?
1. go to New Game+, not New game!!!(All squad statistics and stuff transfer, higher level enemies, rare loot more often)
2. trade weapon in co-op by dropping them from your inventory
but removal of Co-op

how to get scraps?
1. killing each zombie would give you about 10-40 scraps. But if you can't pick them up in time, they would disappear(waste time)
2. decompose stuff. I don’t remember how many you can get clearly, but a level 5 rarity purple weapon would give you 15000.

weapons require a lot of scraps, so don't waste too many scraps to upgrade weapons

scraps amount required for vest and headgear upgrade: initial 50, +50 for each additional level
(double armor after full upgrade)
scraps amount required for weapon upgrade: initial 100, +100 for each additional level, even more than 2500!!!
(after each upgrade, higher dps, from 0 to 4 or even more, that's why we need weapon data)

you might +1 accuracy for some weapons(accuracy data in the old weapon list was inaccurate, probably due to updates, I tried fixing them but I didn't have all weapons)
you might find them in different locations
you might find more than 10 same guns
weapon slots vary from 0-2(except default weapons 3)
slots mean attachments
rarity 1white 2green 3blue 4orange 5purple, rarity sometimes doesn't mean better data(most purple weapons from Jupiter Enterprises have ♥♥♥♥ data)
Range means nothing, if you can see then you can hit, except with pistols (take a few steps forward)
noise also means nothing
? means i don't know or not sure
over 100 weapons

format
name, (dps(min-max), accuracy, magazine, reload time), where you found
(FIXED) means you must find them on the top of dungeons

handguns:
white 1
m9, (15-?, 87%, 9, 2.6s)
green 2
Hand Cannon, (36-54, 86%, 5, 2.3s), Sewer
Desert Eagle, (28-47, 89%, 15, 2.6s), Jupiter/Sewer
Advanced M1911, (38-58, 90%, 7, 1.6s), Utility
M1911, (22-34, 88%, 7, 2.3s), City
blue 3
Advanced M9, (42-67, 91%, 15, 2.1s), Utility
MK23, (58-82, 91%, 7, 1.6s), Science
S45, (51-64, 90%, 13, 2.4s), Science
orange 4
purple 5
Esteban's Gun, (67-139, 95%, 5, 2s), Science
P38, (31-48, 88%, 8, 2.1s), Sewer
Deception, (62-97, 95%, 8, 2.2s), Utility(FIXED)
Faceoff(Körper des Feindes?), (48-60, 93%, 7, 2.3s), Cave
Transformator, (62-?, 95%, 8, 2.2s), Utility

smgs:
white 1
UZI, (81-125, 74%, 32, 1.8s), City/Jupiter
green 2
Worn ZP5, (88-147, 74%, 30, 1.5s), Sewer
Worn EVO 3, (147-176, 75%, 30, 1.5s), Cave
Advanced UZI, (136-?, 75%, 32, 1.8s), Cave
ZP5-PDW, (129-?, 75%, 30, 1.5s), Cave
blue 3
Advanced ZP-5, (144-194, 76%, 30, 1.5s)
ZP9-PDW, (146-202, 75%, 32, 2.5s), Utility
orange 4
EVO 3, (165-205, 77%, 30, 1.5s), Utility
PDW 90, (167-204, 76%, 50, 2.5s)
Vektor, (196-233, 76%, 13, 0.5s), Science
purple 5
RCP90, (?-268-333, 80%, 50, 2.2s), Science
PPSH-41, (?-131, 72%, 35, 1.7s), Jupiter
MKII Sten, (91-125, 73%, 32, 1.8s), Jupiter
SKORPION, (110-152, 72%, 20, 0.5s), Jupiter

shotguns:
white 1
Tactical Pump Shotgun, (56-103, 82%, 7, 4s), City
Breacher Shotgun, (58-75, 81%, 2, 3s), City
green 2
M1014, (89-128, 83%, 7, 2.8s), Jupiter
Double Barrel, (81-112, 81%, 2, 2.7s), Sewer
blue 3
Advanced M1014, (122-156, 83%, 7, 2.8), Cave
Advanced Tactical Pump, (121-163, 84%, 7, 4s)
SSG-12, (115-146, 85%, 14, 4s), Cave Utility
orange 4
Advanced Breacher, (133-167, 85%, 2, 2), Cave
Advanced SSG-12, (140-172, 87%, 14, 4s), Science
purple 5
Boomstick,(?-280-318, 87%, 2, 1.2s), Science
AA-12, (245-271, 87%, 20, 5.5), Science
Platin-Breacher, (150-?, 88%, 2, 3s), Utility

assault rifles:
white 1
M4, (44-84, 76%, 30, 3s), City
Block II, (56-89, 77%, 30, 2.9s), City
SOPMOD, (69-98, 77%, 30, 2.7s), Jupiter
green 2
Mk16, (80-111, 78%, 20, 1.4s)
AR-15, (80-104, 78%, 40, 2.9s)
Mk17, (93-136, 78%, 20, 1.4s), Park
AK-47, (83-111, 75%, 30, 2.4s), City
Mk18 Mod 0, (100-?, 79%, 30, 2.5s), Cave
blue 3
Advanced M4, (106-142, 79%, 30, 3s), Utility
Advanced AR-15, (110-146, 78%, 40, 2.9s), Cave
advanced ak47, (119-?, 77%, 30, 2.4s）
Advanced Mk17, (117-148, 77%, 20, 1.4s), Cave
OBR, (133-200, 81%, 30, 2s), Utility
C8A2, (127-148, 82%, 30, 2.2s),Utility
orange 4
N4, (141-201, 82%, 30, 2.2s), Utility
Advanced N4, (183-222, 83%, 30, 2.2s), Science
Advanced OBR, (163-217, 82% 20, 2s), Utility/Science
purple 5
Desert Warrior, (?-167, 82%, 20, 1.4s), Jupiter
Jungle Warfare, (112-165, 83%, 30, 2.5s), Utility
Patriot AR-15, (104-159, 83%, 40, 2.9s), Jupiter
CTAR-21, (203-247, 83%, 30, 1.9s), Science
Advanced CTAR, (?-304, 84%, 30, 1.9s), Science
Arctic Assault, (229-306, 85%, 30, 2.5s), Science
Patriot SOPMOD, (98-161, 83%, 30, 2.7s), Jupiter
Solid Gold AR-15, (153-208, 83%, 40, 2.9s), Cave
Solid Gold Block II, (146-202, 84%, 30, 2.9s), Cave
Solid Gold Mk17, (167-210, 85%, 20, 1.4s) Utility
Breach & Clear M4, (6-333, 84%, 30, 3s), Jupiter(FIXED)/Sewer
Sid Tripp's M4 : (171-222, 85%, 30, 3s), Science
Hood rifle, (155-?, 84%, 30, 2.4s), Cave

lmgs:
white 1
Mk46, (82-106, 69%, 100, 5s), City
green 2
M60, (119-173, 70%, 100, 4.8s), Jupiter
blue 3
Mk43 Mod 0, (131-188, 70%, 200, 8s), Utility
Advanced Mk46, (153-212, 71%, 100, 5s), Utility
orange 4
Advanced M60, (226-250, 69%, 100, 4.8s), Science
Adv. Mk43 Mod 0, (219-250, 71%, 200, 8s), Science
Shrike, (164-234, 71%, 75, 3.8s), Utility
Advanced Shrike, (234-264, 72%, 75, 3.8s), Science
purple 5
Lone Soldier, (182-218, 72%, 100, 5s), Sewer(FIXED)
One Man Army, (212-253, 73%, 100, 5s), Utility
Bloodthirst, (305-352, 75%, 75, 3.8s), Science
Taste The Rainbow, (352-363, 74%, 75, 3.8s), Science
Seekrieg, (153-?, 71%, 100, 5s), Jupiter

Snipers:
white 1
KAR98K, (47-79, 89%, 5, 2.6s), City
worn mk13 mod5, (?-72, 89%, 5, 2.6s)
green 2
Mk13 Mod 5, (96-123, 91%, 10, 2.5s), Sewer
Hunting Rifle, (64-96, 90%, 15, 3.7s), Sewer
modified kar98k, (?-86, 90%, 5, 2.6s)
blue 3
Adv. Mk13 Mod 5, (123-144, 92%, 10, 2.5s), Utility
M14EBR, (128-180, 92%, 10, 2.2s)
SVD, (102-142, 90%, 10, 2.8s), Cave
orange 4
DSR-1, (139-208, 92%, 5, 2.2s) Utility
Advanced M14EBR, (197-230, 93%, 10, 2.2s), Science
purple 5
Advanced DSR-1, (236-264, 93%, 5, 2.2s), Science
Archimedes, (250-278, 93%, 5, 2.2s), Science
Punisher, (125-174, 92%, 5, 2.2s), Cave(FIXED)
Swamp Thing, (174-233, 92%, 5, 2.2s), Utility

Special(assault rifle):
purple 5
XM25 CDTE, (759-987, 82%, 30, 1.9s), Science(FIXED)
best weapon, 1 shot requires 5 bullets, explodes, even friendly fire

you won't need them at all, useless, rare, can only be used as collections(you may get 10 chemlights in 1 completed round at most)
they all have rarity but I don't care

medical
energy drink: improve reload, move and etc. speed
defibrillator: revive 15% health
adrenaline shot: +luck and evasion
small medkit: 25% health
medkit: 50% health
large medkit: 80% health
group medkit: range heal(maybe 25%?)

explosive
breach charge: breach door with explosion(maybe 4 dmg?)
smoke grenade
signal flare: draw zombies for a while(?s)
flashbang grenade: stun for a while(?s)
hornet’s nest: better flashbang(?s)
mine(?dmg)
frag grenade(center about 350 dmg)
molotov(?dmg)
white phosphorous grenade(?dmg)
chemlight: remove war fog few minutes(?s)

uniforms(like water off a duck's back):
white 1
combat shirt khaki
combat shirt black
green 2
cp ranger acu
cadpat acu
seal acu
ranger acu
sas raid
purple 5
pcu jacket khaki
pcu jacket sea green
pcu jacket urvan grey

headgears:
white 1
black ballcap, light
ballcap cadpat, light
ballcap dcu, light
boonie hstblack, light
skullcap, light
skullcap khaki, light
skullcap olive, light
ranger beret, light
airborne beret, light
green 2
lightshemagh white, light
mich 2000, 25-50, medium
mich 2000 camo, 30-60, medium
mich 2001, 40-80, medium
blue 3
mich 2000+, 35-70, medium
mich 2000 nvg, 35-70, medium
orange 4
black beret, light
purple 5
col. frost’s beret, light
sheriff hat, light
air frame, 55-110, medium
Kiver-M, 65-130, heavy, lab
Ballistic Helmet, 55-110, medium

vests:
white 1
spec ops plate carrier, 30-60, heavy
green 2
rbss, 15-30, light
spear, 25-50, medium
spear rba, 40-80, heavy
blue 3
6094, 20-40, light
ciras, 30-60, medium
Special Forces CIRAS, 50-100, heavy
Taktik Gen lll, 37-74, medium
orange 4
jpc, 25-50, light
pico, 35-70, heavy
purple 5
Gladiator, 60-120, heavy
Plate Carrier, 44-88, medium

dislike in breach and clear, +0.1 rate of fire means higher fps

gas systems:
durable gas system: accuracy+3, rate of fire-0.1
high pressure gas system: damage+0.2, accuracy-3, range+0.1
piston gas system: damage+0.1, accuracy-1, range+0.1
short stroke gas system: accuracy-6, rate of fire+0.15

grips:
custom foregrip: accuracy+2
angled grip: accuracy+3
operator grip: accuracy+1

muzzles:
suppressor: damage noise-0.15
tripletap muzzle: accuracy+1
short suppressor: damage noise-0.1
vortex muzzle: accuracy+1

side rails:
pistol light: accuracy+1

sights:
advanced holographic sight: accuracy+3

triggers:
competitive trigger: accuracy+2, rate of fire-0.1
2-stage trigger: accuracy+1
milspec trigger: accuracy-1, rate of fire+0.1
match trigger: rate of fire+0.1

upper rails:
peq2 ir: accuracy+1
peq15 ir: accuracy+2
ipim ir: accuracy+4