The Beretta M9 is seen in the holster of a US Army soldier in "A Perfect Day for Bananafish", which Max Glenreed uses to disable Griffin Callenreese during his crazed rampage in the Iraq War.
Beretta 92F
A Beretta 92F seems to be in "In Another Country", ditched in an apartment Ash inspects.
Beretta 92FS Compact
The Beretta 92FS Compact appears to be used with two Triad 49ers recruited by Yut Lung at the end of "As I Lay Dying". It appears to have a wood-type grip frame installed.
Beretta 93R
The Beretta 93R can be seen in the cache of pistols which are provided to Ash in "The Beautiful and Damned".
Browning Hi-Power
The Browning Hi-Power can be seen in the cache of pistols which are provided to Ash in "The Beautiful and Damned".
Colt Government Model
What appears to be a Colt Government Model is seen in "The Beautiful and Damned" with the Fly.
CZ P-09
The CZ P-09 can be seen in the cache of pistols which are provided to Ash in "The Beautiful and Damned".
Desert Eagle
The Desert Eagle can be seen in the cache of pistols which are provided to Ash in "The Beautiful and Damned".
Glock 17
The Glock 17 is seen with some New York Police Department officers, when the Glock 19 should be used as their main sidearm. Guards employed at the National Center of Mental Health and Wellness use them as their sidearm. Ash uses it from time to time when he doesn't get to use his revolver. Lao Yen Tai draws one to shoot at Ash in "As I Lay Dying", but was disarmed instead.
Glock 19
The Glock 19 is used by Golzine mob Beaux voyous Marvin Crosby as his sidearm, only seen in "In Another Country". Ash briefly takes one from the basement armory of Dino's estate in the middle of "Babylon Revisited" with a desert tan color. Eiji Okamura uses it in "The Unvanquished" briefly before Ash takes it while raiding Golzine's party.
Heckler & Koch USP
The Heckler & Koch USP is used by Golzine mob Beaux voyous' as their standard pistol with Ash using it briefly, first seen in "My Lost City". Colonel Edward Foxx appears to use it, first seen in "For Whom the Bell Tolls".
Heckler & Koch USP Compact
The Heckler & Koch USP Compact appears to be used by Sergei "Blanca" Varishkov instead of the P250 Compact previously seen in other episodes in "The Catcher in the Rye".
Heckler & Koch VP9
The Heckler & Koch VP9 is seen with an armed man to threaten Lao in "The Unvanquished".
Llama III
The Llama III can be seen in the cache of pistols which are provided to Ash in "The Beautiful and Damned".
M1911A1
A M1911A1 is given to Eiji by Ash after they go into hiding in "From Death to Morning" as his sidearm to protect himself. It's seen with other characters from time to time.
Makarov PM
The Makarov PM can be seen in the cache of pistols which are provided to Ash in "The Beautiful and Damned". It's seen in "The Snows of Kilimanjaro".
SIG-Sauer P250 Compact
What seems to be the SIG-Sauer P250 Compact is used by Eiji in "The Garden of Eden" after he breaks out of Yut-Lung's custody. It's also seen in "Islands in the Stream", "Ice Palace" and in "The Undefeated".
Walther PPK
The Walther PPK is seen in "This Side of Paradise" by Abraham Dawson.
Unknown
Revolvers
Smith & Wesson Model 19
A Smith & Wesson Model 19 is used by Ash, first seen in "From Death to Morning" after he goes to hiding with Eiji and Shorter. Frederick Arthur hands one to Ash in "Save Me the Waltz".
Smith & Wesson Model 27
The Smith & Wesson Model 27 revolver is used by Aslan Jade Callenreese aka Ash Lynx as his main sidearm in the show. Eiji Okumura handles it briefly in "A Perfect Day for Bananafish". The manga source that it's chambered to load .357 Magnum rounds. It's later seen in "The Beautiful and Damned" when he gets back to New York, ditching the Model 19. Sing Soo-Ling hands Ash his revolver in "The Snows of Kilimanjaro".
It appears to be briefly seen in the second opening sequence, "FREEDOM", from the episode "Tender is the Night".
Smith & Wesson Model 60
What appears to be the Smith & Wesson Model 60 is used by Shorter Wong in "This Side of Paradise".
Submachine Guns
Heckler & Koch MP7A1
The Heckler & Koch MP7A1 is seen in "Babylon Revisited" and "The Killers" by some Golzine mob Beaux voyous' as their standard submachine gun. It's seen with Yut-Lung's faction, fist seen in "The Unvanquished". Some of Foxx's mercenaries use them, first seen in "As I Lay Dying".
Ingram MAC-10
Ingram MAC-10s are seen in "The Snows of Kilimanjaro". Cain and some of his Black Sabbath gang members use them in a drive-by in "The Unvanquished" and later on in "The Undefeated". Ash's allies and gang use them after Ash is rescued afterwards.
Intratec TEC-9
What seems to be the Intratec TEC-9 is used by some of Arthur's gang members in "The Snows of Kilimanjaro". Sing and his Triad faction use them during a raid on Golzine's party and later on, with Cain and the Black Sabbath gang in "The Unvanquished" and get distributed to other non-BS gangs in "The Undefeated".
Assault Rifles
AK-47
Ash, Max and Ibe raid the basement armory of Dino's estate after their escape in "Babylon Revisited". The numerous AK-47s can be seen here. It's seen with the various gang factions united to take on Golzine near the end of the show.
Colt M4A1
Colt M4A1s are used by US Army soldiers in the prologue sequence in Iraq in "A Perfect Day for Bananafish". M4A1s with desert tan Magpul furniture are used by Foxx's mercenaries, first seen in "The Undefeated".
M16 Rifle
Ash, Max and Ibe raid the basement armory of Dino's estate after their escape in "Babylon Revisited". The numerous M16 Rifles with the M203 can be seen here.
Remington ACR
The Remington ACR is seen with Ash and Max in "Babylon Revisited".
Battle Rifles
FN FAL
Ash, Max and Ibe raid the basement armory of Dino's estate after their escape in "Babylon Revisited". The numerous FN FALs can be seen here.
Carbines
SKS
A SKS rifle with a scope mounted on the receiver is used in "From Death to Morning" by one of Arthur's crew to snipe at Ash from a moving truck.
Savage 99
A Savage 99 can be seen used in "The Rich Boy" with Jessica Randy.
Sniper Rifles
Mosin Nagant "Archangel"
A Mosin Nagant "Archangel" is used by Blanca, first seen in "The Killers" when he goes on an assassination mission.
SVDK
The SVDK is used by Blanca during the assault on the NCMHW in "The Catcher in the Rye".
Machine Guns
Browning M2HB
The Browning M2HB mounted on US Army Humvees in the Iraq War in "A Perfect Day for Bananafish".
M61 Vulcan
The M61 Vulcan is seen in "This Side of Paradise" with USAF F-16s in a flashback sequence in the early days of the Iraq War.
M134 Minigun
The M134 Minigun is seen in "The Catcher in the Rye" in a Sikorsky UH-60M Black Hawk used by Foxx's mercenaries.
Grenades
Mk 2 hand grenade
A Mk 2 hand grenade is used by Ash during the escape from Dino's estate in "Babylon Revisited". Jessica later uses it in the NCMHW raid in "The Catcher in the Rye".
Grenade Launchers
M203
Ash, Max and Ibe raid the basement armory of Dino's estate after their escape in "Babylon Revisited". The numerous M16 Rifles with the M203 can be seen here.