This is what I've gathered so far, but it was from latest beta, it could be inaccurate, especially the damage. Anyway, the first column of number (x-xx) is damage, second (xb) is weight. The last is caliber, except for shotgun since shotgun all use 12 gauge, the last number there is range.
HANDGUNS:
Handgun_Tier_1_1: VP912: 6-9, 3b, .38
Handgun_Tier_1_2: Navy Rev: 9-14, 3b, .38
Handgun_Tier_1_3: P38: 7-12, 3b, .38
Handgun_Tier_2_1: Makarov: 8-13, 3b, .38
Handgun_Tier_2_2: Midnight Rev: 6-10, 3b, .38
Handgun_Tier_3_1: .38 Rev: 15-18, 3b, .38
Handgun_Tier_3_2: Beretta: 14-27, 3b, 9mm
Handgun_Tier_4_1: Glock17: 14-19, 3b, 9mm
Handgun_Tier_4_2: Peace Rev: 28-40, 3b, .45
Handgun_Tier_5_1: Widow Rev: 16-19, 3b, .45
Handgun_Tier_5_2: Glock19: 11-13, 3b, 9mm
Handgun_Tier_6_1: Deagle: 32-36, 3b, .45
Handgun_Tier_6_2: 1911: 16-20, 3b, .45
SMG:
SMG_Tier_1_1: MP40: 6-9x3, 4b, .38
SMG_Tier_1_2: Sten: 5-6x3, 4b, .38
SMG_Tier_1_3: Mk27: 8-11x3, 4b, .38
SMG_Tier_2_1: Skorpion: 22-27x3, 4b, .38
SMG_Tier_2_2: PPSH: 20-36x4, 2b, .38
SMG_Tier_3_1: UZI: 14-18x3, 4b, 9mm
SMG_Tier_3_2: Mac17: 10-20x5, 3b, .45
SMG_Tier_4_1: TMP: 8-12x3, 5b, 9mm
SMG_Tier_4_2: Thompson: 8-12x5, 5b, .45
SMG_Tier_5_1: MP5K: 7-10x3, 5b, 9mm
SMG_Tier_5_2: UMP9: 9-10x3, 5b, .45
SMG_Tier_6_1: MP5AR: 15-18x3, 5b, .45
SMG_Tier_6_2: AR-45: 28-36x?, 5b, .45
ShotGun:
Shotgun_Tier_1_1: pump. 14-18.5b.15m
Shotgun_Tier_1_2: sawoff 13-16 4b 9m
Shotgun_Tier_2_1: coach, 21-28, 5b, 12m
Shotgun_Tier_2_2: leveraction 18-34 6b 10m
Shotgun_Tier_3_1: M37 28-38 5b 14m
Shotgun_Tier_3_2: SOSG 18-24 5b 14m
Shotgun_Tier_4_1 overunder 21-28 5b 13m
Shotgun_Tier_5_1 holdup 21-25 5b 13m
Shotgun_Tier_5_2 tactical 20-30 5b 13m
Shotgun_Tier_6_1 SPAZ 50-60 5b 13m
Shotgun_Tier_6_2 jackhammer 25-30 5b 13m
AssaultRifle:
AssaultRifle_1_1 m1 6-10 8 556
AssaultRifle_1_2 m14 7-13 9 556
AssaultRifle_1_3 rusty 10-14 7 556
AssaultRifle_2_1 M4 18-29 8 556
AssaultRifle_2_2 Famas 12-17 8 556
AssaultRifle_3_1 HK33 15-19 8 556
AssaultRifle_3_2 M16 18-23 8 556
AssaultRifle_4_1 AK47 30-38 5 762
AssaultRifle_4_2 AUG 17-22 5 556
AssaultRifle_5_1 G3 18-23 5 762
AssaultRifle_5_2 AK97 36-40 9 762
AssaultRifle_6_1 FAL 21-25 5 762
AssaultRifle_6_2 G41 22-28 5 762
Sniper:
Sniper_Tier_1_1 Hunting 12-16 8 3006
Sniper_Tier_1_2 R270 12-22 8 3006
Sniper_Tier_1_3 m40 14-17 8 3006
Sniper_Tier_2_1 G43 21-28 8 3006
Sniper_Tier_2_2 SKS 18-26 8 3006
Sniper_Tier_3_1 type88 30-34 8 3006
Sniper_Tier_3_2 M24 34-40 8 3006
Sniper_Tier_4_1 SR2000 30-38 5 762
Sniper_Tier_4_2 SVV 35_45 30 762
Sniper_Tier_5_1 AWP 41_47 30 762
Sniper_Tier_5_2 SVD 40-50 8 762
Sniper_Tier_6_1 PSG 40-55 30 762
Sniper_Tier_6_2 M82 40-60 30 50s
Machinegun:
Machinegun_Tier_1_1: M2 3-5x8 556
Machinegun_Tier_2_1: Bren 9-11x5 556
Machinegun_Tier_3_1: bar 10-13x6 556
Machinegun_Tier_4_1 m60 14-18x5 762
Machinegun_Tier_5_1 SAW 15-20x6 762
Machinegun_Tier_6_1 minigun 12-15x10 762
Ammo:
Ammo_.38_S
Ammo_9mm_S
Ammo_.45_S
Ammo_.30-06_S
Ammo_5.56mm_S
Ammo_7.62mm_S
Ammo_.50_S
Ammo_12-00