Yuri (AKA "Yurippe") uses a Beretta 92FS Brigadier Inox as her handgun of choice. She actually has two of these guns and at one point she dual wields both of them.
Glock 17
Otonashi Yudzuru use Glock 17s (2nd or 3rd Gen.). Unfamiliar with firearms, Otonashi nonetheless trains with the Glock until he becomes a proficient shooter.
Stechkin APS
Noda prefers to fight with his halberd, but at one point he is forced to use a Stechkin APS gun against Angel.
L.A.R. Grizzly
TK occasionally uses an L.A.R. Grizzly (calibre unknown)
Browning Hi-Power
TK's other handgun of choice is a Browning Hi-Power. He dual wields it along with the L.A.R. Grizzly.
Desert Eagle
Takamatsu carries a Desert Eagle. However it is not quite noticeable in the anime.
Smith & Wesson 645
Hinata carries a Smith & Wesson 645. He is quite familiar the gun and is a good shot.
P226
Ooyama's signature sidearm. His primary weapon is actually a sniper rifle, but he draws his pistol during close-range fighting.
H&K P7
An H&K P7 (calibre unknown) serves as Matsushita's sidearm during the SSS journey to the ruins of the Guild.
USP
Ayato Naoi is armed with a 9mm USP.
Sub-Machine Guns
PP-19 BIZON
TK preferred primary weapon is the PP-19 Bizon sub-machine gun, first seen during the first assault against "Angel"
PPSH 41
Fujimaki carries a PPSh-41 during the battle with "Angel"
TDI Vector
Towards the end of the series Yurippe uses a TDI Vector as a primary weapon. She also has two of these SMGs just like her handguns.
Assault Rifle
HK 33
HK33K
SG 552
Takamatsu carries a SIG SG 552
CQB-R
Guild leader Cha presents a M4A1CQBR assault rifle to Yuri when she runs out of ammo for her TDI Vector submachine gun.
Oyama's primary weapon of choice is a Remington M700. He serves as the main sniper of the SSS.
H&K PSG-1
M14 DMR
Hinata is armed with M14 rifles when both of he and Otonashi serve as lookouts as they scan for their enemy, student council president Angel
Galil Sniper Rifle
While serving as a lookout along with Hinata, Otonashi is equipped with a Galil Sniper Rifle.
M-200 Intervention
Yuri uses a CheyTac M200 during the first episode when she snipes her nemesis, Angel. Being new to the Afterlife world Otonashi asks if the gun Yuri uses is real. He also discourages Yuri from firing at Angel.
Rocket Launcher
AT4
Being the heavy weapons guy of the team, Matsushita use an AT4 against Tachibana Kanade (Tenshi), to little avail.