M6C magnum

The M6C Personal Defense Weapon System, otherwise known as the M6C Magnum Sidearm, is a United Nations Space Command sidearm available in Halo 2

Design Details
The M6C Magnum Sidearm, is a short-medium range UNSC handgun, it is one of the earlier models of the M6 series pistols, that was distributed to members of the UNSC Marine Corps, especially those of vehicular crews. This particular M6 model is usable exclusively in Halo 2. It is considered a weak weapon when compared to other M6-series weapons with reduced accuracy, a shorter effective range, and less efficiency against shielded, armored, and soft targets. SPARTANS can dual-wield this model.

The M6C is a semi-automatic, recoil-operated, magazine-fed handgun. It most likely has DA, or double-action only trigger due to the fact that there is no external hammer. It fires the M228 12.7mmx40mm SAP-HP round (Semi-Armor Piercing, High Penetration) from a 12 round magazine. It has a considerably high rate of fire (6 rounds/sec or 360 rounds/min) with a limited maximum effective range, being able to hit a target accurately at only about 20 meters.

The M6C uses the short recoil principle. This means that the trigger needs to be pulled after every shot for the next round to be fired. Because it is semi-automatic, the gun will cock itself after every shot due to recoil and will continue to do so until the magazine is empty. The recoil comes from the gases of the rounds fired. The gases force the slide, located on the top of the gun, backward. The slide not only absorbs the force of the gases but it also uses the force to eject spent casings out of the ejection port and load new rounds into the chamber. It also re-cocks the gun. Of course, before the first round can be fired, the round must be chambered. This is done first by inserting a magazine with ammunition into the grip of the weapon and second by pulling the slide back completely and letting it launch forward, chambering a round on the way. There is a small, red rectangular box on the flat back of the slide that protrudes out slightly when the weapon is cocked. Once this is done, the safety, located at the back of the slide on both sides, must be switched off or the weapon will not fire. Once all the rounds have been spent, the slide catch, a rectangular lever located above the trigger, is forced upward and “catches” the slide by a little notch. To reload, the empty magazine must be removed and this is done by using the magazine release button which is located on the grip. Once the empty mag is out, a fresh one can be inserted. Once the fresh mag is inserted, the slide catch is pressed downward and the slide chambers a round. In Halo 2, this reload is cut down to a simple ejection of one mag and an insertion of another, disregarding the slide catch portion of the reload. This was probably to cut down on reload time for multiplayer. If there is still a round in the chamber when reloading, than the "Halo 2 reload" would be all that is required.

Ammunition
The M6C Magnum, uses 12.7mmx40mm (.50 caliber) Semi-Armor-Piercing, High-Penetration rounds. These rounds have a jacket of copper or nickel which encloses a more frangible metal projectile that will deform shortly after penetration. When the round hits a hard object such as body armor, the jacket will temporarily help maintain the shape of the projectile so that it has a better chance of penetration. A second impact against bone or solid muscle mass inside the target's body is usually enough to complete the jacket's rupture, at which point the projectile mushrooms and franges into smaller pieces, causing a large number of wound channels and maximizing damage. These rounds are typically more effective against infantry as opposed to armor-piercing rounds due to a larger dump of KE, resulting in better stopping power, and also to the process described above, with an armor-piercing round speeding through the target's body without causing as much trauma, creating a scenario where a wounded enemy can still be an effective combatant until they bleed out. Despite its usefulness against even armored infantry, the weapon is nearly useless against fully shielded targets, as the ammunition has no secondary effects, and the weapon cannot produce a sufficient volume of fire to make it a reliable shield-breaker.

Spare ammo packets, for the M6C are marked in blue, unlike the M7's spare ammo packets which are marked in red.

Advantages
The M6C Magnum is presented in-game as a defensive sidearm best used against unshielded targets, fairly accurate over short distances, and possessing a relatively small magazine as compared to other human firearms. That said, as long as the operator knows how and when to utilize the M6C, it can be an effective sidearm in Multiplayer and to an even greater degree in Campaign.

In Multiplayer, if the operator is skilled in consistent head-shotting, it can be an efficient cleanup weapon against unprotected players, causing relatively little damage to active shields. It particularly shines at close range when carried with or dual-wielded alongside an M7 or a plasma-based weapon, with the M6C performing the coup de grace after the victim's shields have been stripped away by the primary weapon. This one-two system enables a proficient player to quickly and efficiently put-down large numbers of single opponents, though the tactic can quickly fail when attempted against multiple targets, unless all but one is distracted or otherwise a non-factor. Wielding a pair of M6Cs can enhance their efficacy in dealing with multiple unshielded enemies, but if the targets are not at close range, their accuracy and effectiveness quickly dwindle, and the operator will be left vulnerable and unable to return fire for a significant amount of time as both pistols are reloaded unless they can switch to another weapon, in addition to the liability of being attacked while searching for vulnerable opponents and being able to respond only with pistol fire.

The M6C is best used in Campaign in a similar manner to Multiplayer, with the difference of being altogether more effective due to the prevelance of naturally unshielded enemies like Grunts and Jackals. Drones and Flood combat forms can be dispatched in as few as 2-4 shots. The M6C is also effective against unshielded Elites and Brutes who have had their helmets knocked off, with just a single headshot required to kill either.

In Halo 2 matchmaking the M6C was initially an extremely powerful weapon. When dual-wielded 2 M6C Magnums could easily kill an enemy even at range, kill the pilot of a Banshee or both the driver and gunner of a Warthog. However, once both magazines are spent the wielder is extremely vulnerable to counter-attack due to long reload times. After the 1.1 auto-update M6C Magnums became significantly weaker in matchmaking with its primary use being in SWAT gametypes.

Disadvantages
After the Halo 2 patch the Magnum was weakened to ensure balance in the Halo sandbox. The biggest disadvantage about the M6C, compared to previous and current versions of the Pistol in Multiplayer, is its inability to take down players at medium or long ranges. The weapon’s accuracy alone is inferior to the other M6 models, about 1/5 as accurate as the M6D Pistol, having a large shot spread at close ranges. This, combined with its minimal damage against current shield systems, makes it a poor weapon of choice when faced with shielded opponents, especially at distance. It is, however, more effective against unshielded targets and those wearing hard/soft armor, being able to kill most targets in 1 shot to the head or a few shots to the body, although it still doesn't achieve the power of it's successor, the lack of a scope also reduces the weapons effectiveness. Unless a player is Dual-Wielding another weapon the M6C by itself is not a enough to take on a player. In Campaign Elites who are fully shielded and Brutes with helmets, require more shots to kill them, 9 shots to the head of a Minor, 14 shots to the head of a Major or Honor Guard, and between 28 and 30 shots to the head of an Ultra; 3 shots to the head of a helmeted Brute. This weapon is less effective in engaging Hunters, which require a large number of rounds to their exposed flesh to kill them.

Influences
One possible influence on the design of the weapon is the Walther P99. Another possible influence could be the FP-45 Liberator, a weapon designed in the United States during World War II. The long handle, but short barrel is an obvious feature.

It is possible that the M6G is the UNSC Marine Corps Standard Sidearm, as the M6C seems to use older technology, and the M6D seems to use technology reserved for Spartan-IIs and other Spec-Ops units. That would mean, that the M6C is the Navy's variant of the M6 line.

Due to the numbering of the M6C, that would mean that this pistol went into production before the D and G variants, meaning the M6C was around before Halo: Combat Evolved, which uses the M6D. This supports the idea that the M6C uses older technology. Also, in Halo: Combat Evolved the M6D was issued as the crew were given those weapons for the special mission. In Halo 2, the M6C was the standard issue, yet old, sidearm for the Navy and Marine forces defending Earth. The M6G came in during the rearmament for the request for new weapons to help defend Earth during the Battle of Earth.

Campaign

 * In Campaign The M6C is best used when Dual-Wielding another weapon, Two M6C's will be very effective at taking down Covenant quick.
 * Headshots (which are always a 1-hit kill except against shielded or helmet-wearing enemies) are essential for effective use of the M6C, since torso shots do mediocre damage. A single M6C bullet does about the same amount of damage as a Battle Rifle round, except the M6C is single shot and has a clip size of 12 whereas the Battle Rifle fires in 3-round bursts and can fire 36 rounds before needing to be reloaded.
 * Dual-Wielding the M6C with a Plasma Pistol is arguably the best combo in the game.

Multiplayer

 * If you have no other option available, dual-wield the M6C with another weapon to maximize your chances until you find a weapon that you can use.
 * If forced to use a single M6C be sure to get up close to the enemy player, fire to lower his shields and then melee attack for an effective kill.
 * Using the Plasma Pistol with the M6C is often one of the easiest ways to assure a kill.

Trivia

 * A Suppressed variant is available to UNSC Special Forces. - (Halo 3:ODST)
 * The Halo 2 Post Game Carnage Report Breakdown Tab on Bungie.net shows the weapon as "Magnum M6G Pistol" even though the game manual states it is the M6C model.
 * If aimed directly at an enemy's head a red dot will appear in the center of the crosshair.
 * The pistol is a dark greyish color rather than a Whitish-silver color like other variants, but some versions have been noted to have a silver colour, like John Forge's pistol.
 * The M6C has no hammer and can be implied that it has an internal firing pin or striker that is spring loaded, similar to that of a Glock handgun.