Possibly based on real but not sure weapons:

Pistol

The Pistol.

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Holding a Pistol.

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The player character somehow ejects the magazine by fiddling with the Slide.

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Inserting a fresh magazine.

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Chambering the weapon.

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Holding Dual Pistols, the left hand is unanimated and clips through the gun when not firing/reloading/aiming.

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Reloading Dual Pistols.

Commando Rifle

The Commando Rifle is an alternative assault rifle that can be fitted with a scope and a "Flash" attachment located under the barrel that blinds opponents with a bright light.

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An unscoped Commando Rifle.

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Holding a scoped Commando Rifle while looking at an NPC holding a "modernized" version of the WW1 Machine Gun inspired Assault Rifle from Iron Storm that functions as the basic assault rifle.

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Reloading a scoped Commando Rifle via pulling the charging handle to eject the magazine.

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Inserting a new magazine into the Commando Rifle.

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An NPC holds a Commando Rifle in a Black Out Saigon cutscene.

Sniper Rifle

The "Sniper Rifle" looks an advanced version of the "Dragunov Snayperskaya sniper rifle" from Iron Storm, linking the two games.

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Holding the Sniper Rifle, the cheapest version lacks a scope.

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Holding the Sniper Rifle, with a scope this time.

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Using the bolt after firing.

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Changing the magazine.

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A "James Anderson" with his Sniper Rifle as a BOS opponent in Black Out Saigon as a reference to Iron Storm's protagonist with the same name who also used the weapon.

"Intensive Care"

The "Intensive Care" is a missile weapon introduced in the expansions, it can be upgraded with a scope and is the most damaging weapon in the game, being capable of destroying exoskeletons far faster than other weaponry.

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The "Intensive Care" in the game's manual.

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Holding the "Intensive Care".

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Reloading the "Intensive Care".

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Holding a scoped "Intensive Care".

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View through the "Intensive Care"'s sight.