The Diamond Back .357 is a .357 magnum revolver made by Mustang Arms Ad-Tech Ltd. This revolver is rather innovative, using a revolving cylinder magazine and a hybrid cartridge system to combine reloading speed with reliability and accommodate multiple ammo types.
The Diamond Back uses telescopic ammunition, in which the projectile is completely enveloped in the case by the propellant. This revolver can also use heavyweight .357 magnum special explosive rounds. It can accept 5, 6 or 7 round cylinders. The weapon uses a side break action rather than conventional swing-out cylinder for reloading. Prior to speed upgrades, the Diamond Back reloads rather slowly, but once adequately invested in, an entire cylinder can be changed within mere moments.
Un-upgraded, the Diamond Back offers great stopping power and a tremendous bullet damage, capable of dropping heavy troops and bots in a single shot.
When upgraded with the explosive round modification, it becomes even more powerful, killing all non-boss enemies with 1-2 shots and bosses with 3-7 depending on whether they are a direct hit near a critical area. Given its availability in the environment or on downed enemies, and its raw power-to-size ratio in the inventory, the revolver is an economical choice for players who prefer combat to stealth in boss fights or enemy encounters. A single cylinder of reserve ammunition can hold up to 50 rounds while using only two slots of inventory space, far exceeding the same explosive power and storage of grenade launcher ammunition or frag grenades.
A major drawback to using this weapon is its somewhat low accuracy. Firing the Diamond Back without aiming will almost always cause the bullet to hit off-target, unless a Laser Aiming Module is attached, after which it becomes greatly more accurate. Its heavy recoil also contributes to its high miss rate, but can be circumvented with the right augmentations.
Ammunition is very rare at the start of the game, but after locating Isaias Sandoval, it becomes vastly more common.
- The revolver is misaligned when aiming down sights, pointed slightly to the left. Aiming, and continually turning the camera to the right will shift it to it's "correct" position.
- Despite concept art depicting an 8-round magazine upgrade, the maximum capacity in game is 7 rounds. This reduction was likely for balancing purposes.
- The first visible in-game instance of the Diamond Back is at the end of the prologue, being wielded by a wounded Jensen in a futile attempt to ward off Jaron Namir, before being promptly disarmed and the weapon turned against him.
- Despite having it in the cutscene, Jensen cannot wield it during the opening mission. The first time it can be acquired is by choosing the short-ranged, lethal option at the start of the mission at the Milwaukee Junction plant.
- When confronting Zeke Sanders, his revolver sports the explosive round upgrade during the cutscene, but no longer has it when Jensen can start talking to him. This was likely done to prevent the player from acquiring the explosive round upgrade so early in the game.
- No enemy is encountered that has a revolver upgraded with the explosive round upgrade.
- A custom-made Diamond Back .357 revolver made specifically for Pieter Burke. It can be taken from the safe in his office anytime before going down to Rifleman Bank Station's hidden lab, or taken off of Burke himself during the final battle.
- If taken from his safe, it comes pre-equipped with a laser sight. If taken from Burke, it lacks one but one can be installed.
- Besides the laser sight, this revolver cannot be upgraded.
- Its has a higher rate of fire that is possible on the standard revolver, 1 upgrade above the base reload speed, 2 upgrades to its damage, and the base level ammo capacity.
- Its model has the upgrade for explosive rounds, but the rounds do not explode.
- If taken from Burke's safe, Burke will arm himself with a Hurricane TMP for the final battle as a replacement.
- This is the only revolver that can be found on Rifleman Bank Station and the only place to acquire ammo is a few boxes from Garvin Quinn and what is found in Burke's safe, making ammo extremely rare. Luckily the strength of the weapon means that targets won't survive more than 1 or 2 body shots, so you won't need much ammo if you aim carefully.
- The Diamond Back .357 uses the Dardick tround concept.
- A version of this weapon was ported into Team Fortress 2 as a promotion weapon for the Spy Class. It has the special ability to accumulate critical hits for every Engineer building sapped or successful "Backstab" attempt. The Team Fortress 2 Diamond Back was modeled after the Explosive Rounds-upgraded DX3 revolver, as evident by the barrel, but uses the traditional swing-out cylinder style instead of DX3's break-action and removable "magazine".
- The Diamond Back is most likely a reference to Colt's revolvers named after snakes. The real-life Diamondback is not chambered in .357 magnum; however, an eBook in the game references "an old classic, the .357 Python," which is also a real gun that does fire the .357 magnum cartridge, (the real-life Diamondback is basically a Python chambered in .22LR and .38 Special cartridges).