In L4D11TY, there are 6 weapon classes. Pistols, Submachine Guns, Shotguns, Assault Rifles, Sniper Rifles and LMG's. Each tier a new weapon variant is introduced for each class.
Pistols[]
Pistols are the basic secondary weapon. They have unlimited ammunition except in Realism mode. They provide basic backup capabilities, and the later ones available can even provide a replacement for primary weapons.
Tier 1: Beretta M92F
Tier 2: H&K USP.45
Tier 3: Colt M1911
Tier 4 IWI Desert Eagle
Tier 5: S&W M500
Tier 6: Gauss Pistol
Shotguns[]
Shotguns are the perfect close range weapon. While not having much in the way of accuracy/range, they can tear apart even Advanced Infected hordes in a matter of seconds. The earliest shotgun, the Mossberg 500, is the only shotgun with a long reload time due to it require individual shells to be loaded.
Tier 1: Mossberg 500
Tier 2: Saiga-12
Tier 3: SPAS-15
Tier 4: USAS-12
Tier 5: AA-12
Tier 6: Triple-Barrel Shotgun
Submachine Guns[]
Submachine Guns don't have any major advantages over Assault Rifles in this game, they do however provide higher rates of fire, less weight, cheaper ammunition and modifications at the cost of accuracy and range.
Tier 1: Steyr TMP
Tier 2: H&K MP5K
Tier 3: H&K MP5
Tier 4: TDI Vector
Tier 5: H&K UMP45
Tier 6: FN P90 TACMOD
Assault Rifles[]
Assault Rifles are the primary weapon of most factions in the game. They provide decent magazine size, range, damage and accuracy. All Assault Rifles are generally expensive, but attacking any faction can yield an Assault Rifle or 6 for looting.
Tier 1: Colt M4A1/Colt M16A4
Tier 2: L85A2/FAMAS
Tier 3: SIG-Sauer SIG556/FN SCAR-L
Tier 4: Steyr AUG A3/H&K SL8
Tier 5: H&K HK417/FN SCAR-H
Tier 6: M41A Pulse Rifle
Light Machine Guns[]
Light Machine Guns are generally are risk/reward weapon. While they provide higher damage output and rate of fire than Assault Rifles, they are less accurate, and also heavy, meaning you will be slowed down when using them.
Tier 1: RPK
Tier 2: Colt M16A3 LSW
Tier 3: FN SCAR LSW
Tier 4: H&K MG4
Tier 5: FN Mk48Mod1
Tier 6: Bolt-Gun Minimi
Sniper Rifles[]
Sniper Rifles are ideal for killing something at long range. They are powerful at almost all distances, but up close they are useless, and attachments also cost slightly more for Sniper Rifles. Also, the two Bolt Action snipers are less effective in taking out multiple targets.
Tier 1: Dragunov SVD
Tier 2: L96 Artic Warfare Magnum
Tier 3: Cheytac Intervention
Tier 4: H&K PSG1
Tier 5: Barret M82A1
Tier 6: Rail Driver