Shin Megami Tensei: Digital Devil Saga 2

Shin Megami Tensei: Digital Devil Saga 2 is a 2005 Japanese RPG for the PlayStation 2. After the first game, a tribe of shapeshifters known as the Embryon are sent to a world where the population lives underground in fear of a black sun that makes those who are caught in its rays succumb to "Cuvier Syndrome" which turns them to stone.
The following weapons appear in the video game Shin Megami Tensei: Digital Devil Saga 2:

Pistols

Strayer-Voigt Infinity

In human form Serph's weapon of choice is a Strayer Voigt Infinity 1911, referred to in menus as "Handgun". Fittingly for the main character, but not for a handgun, it is moderately accurate, decently powerful, and features a better than average critical rate.

Strayer Voigt Infinity 1911 - .45 ACP

In the pre-rendered opening animation Serph finds a Cuvier Syndrome victim who tried to commit suicide with a Strayer Voigt Infinity, giving a good view of its rear and top features.

Serph takes the Strayer Voigt Infinity from the dead man when he is ambushed by Karma Society soldiers, show off the 1911 derived trigger. Despite 5 years in a raging sandstorm the gun preforms flawlessly.

Serph teacups his Strayer Voigt Infinity, showing the Asura Project failed to produce a "perfect" combatant.

Argilla teams up with Serph for a combo attack. Serph holds his Strayer Voigt Infinity gangster style. This terrible marksmanship is probably why the Embryon were one of the weakest tribes at the start of the first game.

Submachine guns

Heckler & Koch MP5SD

Some generic Lokapala members use Heckler & Koch MP5SD.

Heckler & Koch MP5SD2 - 9x19mm

The two rear Lokapala hold MP5SDs.

Heckler & Koch UMP45

Cielo uses a stockless Heckler & Koch UMP in battle. The straight magazine indicates it is in .45. It will hit every enemy in battle, but a random number of times.

Heckler & Koch UMP45 - .45 ACP

Cielo holds his UMP in his battle model.

Cielo using his UMP. It's not immediately obvious with his dreadlocks, but close inspection shows he closes his left eye even though he's shooting from the hip.

Shotguns

Knight's Armament Masterkey

Gale's "Assault Rifle" has a Knight's Armament Masterkey attached. He never actually uses it.

Masterkey shotgun mounted on a KAC SR-16 rifle - 12 Gauge

Gale, in human form, attacks some random encounters with his "Assault Rifle"

Remington 870

In human form Roland's weapon of choice is a pistol grip only Remington 870, referred to in game as "shotgun". It hits all enemies for low damage but has a decent critical rate.

Remington 870 Express with TacStar pistol grip - 12 gauge

Roland attacks with his "Shotgun"

Rifles

M16 Based Carbine

Other Lokapala members use M16 Rifle based carbines. Being low poly accessories for generic NPCs that will normally only be seen from a distance, the exact variant intended is impossible to determine.

Original M4 Carbine - 5.56x45mm NATO.

The two front Lokapala hold M4 Carbines.

M16 Rifle

In human form Gale's preferred weapon is an M16 Rifle, of unclear type, with a Masterkey attached referred to as "Assault Rifle". It hits every enemy a random number of times (possibly 0) with fewer hits but higher damage each than Cielo's UMP45.

Masterkey shotgun mounted on a KAC SR-16 rifle - 12 Gauge

Gale, in human form, attacks some random encounters with his "Assault Rifle". Like all members of the Embryon, Gale's technique is pretty terrible.

Heckler & Koch PSG-1

In human form Argilla's preferred weapon is a Heckler & Koch PSG-1 without a scope.

Heckler & Koch PSG-1 - 7.62x51mm NATO

Argilla teams up with Serph for a combo attack.

Launchers

M79 grenade launcher

In human form Heat's preferred weapon is an an M79 grenade launcher, referred to in menus as "Grenade Launcher". Contrary to Heat's brutal nature and being a grenade launcher, it is the weakest gun used by a party member. It does however hit all enemies.

M79 Grenade Launcher - 40x46mm

Heat holds his M79 in his battle model.