The standard-issue sidearm for GUN soldiers in the game is the Heckler & Koch USP Tactical. When Shadow is confronted by the GUN Commander in a cutscene, the Commander attempts to shoot Shadow with his USP Tactical, but misses. The gun has a 10-round capacity in-game, and fires semi-automatically.
In some pre-rendered cutscenes, GUN soldiers use M1911A1 pistols. A silhouette of an M1911A1 also appears on GUN supply crates. Shadow is seen holding an M1911A1 in promotional images and the opening sequence, but he never uses one in game. It's possible that at some point the M1911A1 would have been the standard pistol and was changed
to a USP Tactical.
GUN soldiers also use the Heckler & Koch MP5A3 with the Navy trigger group. The gun is fully automatic with a 20-round capacity while used by Shadow. The opening title sequence of the game shows Shadow a much more detailed and accurate MP5; in this cutscene, Shadow rather infamously cocks the weapon by pumping its handguard like a pump-action shotgun, with the handguard even visibly moving during the animation.
Error creating thumbnail: File missingHeckler & Koch MP5A3 with Navy trigger group - 9x19mmThe MP5A3's in-game model. The weapon lacks a trigger and trigger guard in-game and appears to have a railed handguard which the developers might have mistaken for a pump-action charging handle. Note that the fire selector is on semi-auto, despite being automatic in-game.Error creating thumbnail: File missingShadow carrying an MP5A3 in-game.Error creating thumbnail: File missingShadow loads a magazine into his MP5A3 in the opening sequence.Error creating thumbnail: File missingShortly afterwards, Shadow pumps his MP5A3.
Rifles / Carbines
SIG SG 551
The standard assault rifle used by GUN soldiers is the SIG SG 551. When picked up by Shadow, it has a 30-round capacity.
A heavy machine gun that appears to be loosely based on a Browning M1919 appears in the game. It is mounted on turrets which can be used as a stationary weapon (with unlimited ammo) or destroyed and used as a handheld weapon with a 30 round box magazine (somehow a stock and pistol grip appear on the gun when it is destroyed). The weapon also appears in the hands of GUN combat robots and in crates later on in the game. Oddly, it can be fired faster in semi-auto than in full-auto.
Handheld GE M134 Miniguns can are dropped from GUN's F-6 "Big Foot" Walkers (despite the fact that, like in Sonic Adventure 2, the "Big Foot" walkers are depicted with fictional 3-barreled miniguns). As expected, they are massive in comparison to Shadow and are held by a strange pistol grip. They are arguably the game's best weapons due to their 40-round magazines, high damage, and fast rate of fire, but they are somewhat usurped by their relative sparsity.
Error creating thumbnail: File missingGE M134 Minigun - 7.62x51mm NATOThe GE M134 Minigun's model.Error creating thumbnail: File missingShadow Holding the M134 while an F-6r "Big Foot" fires its rockets at him. Because of the massive size of the weapon, it often clips through the floor. One can also see the 3-barreled minigun depicted on the Mechs.
Launchers
Milkor MGL
GUN soldiers also use the Milkor MGL grenade launcher with the stock and Armson OEG reflex sight removed. It holds six grenades.
FGM-148 Javelin Block 0 with original M98A1 CLU and original BCU (the current production BCU has a mesh heat shield rather than a solid one) - 127mmError creating thumbnail: File missingFIM-92 Stinger with IFF interrogator - 70mmError creating thumbnail: File missingFIM-43 Redeye - 70mmThe "RPG"'s modelShadow holds an "RPG".
M202 FLASH
The "4-Shot RPG" and the "8-shot RPG" appear to be loosely inspired by an M202 FLASH.
An unused weapon icon that depicts a Colt Gold Cup National Match can be found in the games files. It is identified mainly by the slanted slide serrations and the grips. It can be seen in early screenshots.
