BR55 battle rifle

The BR55 Battle Rifle is a United Nations Space Command infantry service rifle, which uses a bullpup configuration. A newer version, the BR55HB SR Battle Rifle has been recently been introduced.

Summary
The BR55 Battle Rifle is a bullpup UNSC rifle. It was already in service by 2525. The M6D pistol in Halo: Combat Evolved was replaced by the Battle Rifle as the primary mid-range UNSC firearm, although the power of the Battle Rifle was reduced compared to the M6D, as was its firepower. Its biggest problem lies in its magazine size combined with the burst fire, giving only 12 bursts before reloading.

Advantages
Designated the BR55 Battle Rifle, it has reasonably high power, a decent rate of fire, and high accuracy with a 2x magnification scope; it can be used to deliver three-shot-bursts accurately from medium-to-long range. In Campaign, the Battle Rifle is useful against just about any infantry units at medium and, sometimes, semi-long range. In multiplayer, four full bursts will kill a fully-shielded opponent, assuming standard shields. Against unshielded enemies in both Campaign and Multiplayer, one headshot results in death. This requires that only one of the three rounds from a 3-shot burst hit an enemy. Therefore, it is possible to kill up to three unshielded opponents in a single burst. It is also a decent anti-sniper weapon or suppressive weapon.

Disadvantages
At longer ranges, it is necessary to minimize strafing movements when firing to avoid "splintering" the shot grouping too much. Since each "shot" is really a three-round-burst, certain movements can break up your shot's grouping and greatly reduce accuracy. This also affects accuracy when firing from a moving vehicle such as a Warthog (especially when firing at a 90-degree angle from the vehicle's heading).

The Battle Rifle is not as effective at close ranges, nor is it effective against Elites due to the slow rate of fire. Each bullet also acts as a tracer which gives away the shooter's position. Also, the range is limited: if a sniper rifle's reticule isn't red when you're aiming at an enemy, the battle rifle won't hit the target.

Tactics for Covenant
Grunts are slow and clumsy, and lack any form of shielding. A single (and commonly easy) headshot or several shots to the body will kill them.
 * Grunt:

Not as effective as against Grunts, as the bullets bounce straight off a Jackal's Energy Shield. When confronted by a Jackal with its shield in defense position, fire a well-placed shot through the small notch, and, as the Jackal recoils from the wound, finish it off with a headshot.
 * Jackal:

At medium range, the rifle is an effective anti-sniper weapon, giving suppresive or covering fire. Since sniper Jackals do not use shields, they can be easily dispatched with a well-placed headshot or a few shots to the body. As always, it is important to always use proper cover when engaging a Jackal sniper. Be careful you don't get sniped if you are forced to stand in the open, though, and be sure the Jackal doesn't recover and fire off a shot. This is extremely important for Legendary battles.
 * Jackal Sniper:

The Elite's energy shield is a great defense to the Battle Rifle. On Normal difficulty, a basic Minor Elite takes four full bursts to the head to kill, while Major Elites take six and Ultras take 12. However, unshielded Elites of any rank will die from a single headshot. Try to keep the rifle leveled at its head, and keep firing till it falls dead. It is advisable to soften an Elite up with grenades, melee attacks, or a plasma pistol's charged shot before engaging them with a BR, especially on higher difficulties.
 * Elite:

You can kill a Brute with 3 headshots, as the first 2 bursts will knock off the helmet, then the follwing headshot will kill the Brute. However, shooting a Brute in the torso is not particularly effective due to their extreme resilience. (Note: The only stage in which Brutes can be fought with a Battle Rifle is High Charity. The weapon can be aquired from the Flood Combat Forms in that level.)
 * Brute:

Dodge behind them, and fire as many bursts as possible into their back before they turn around. Be careful when fighting an enraged Hunter, as they can backhand you and kill you with a single strike. It can take quite a few bursts to kill a Hunter, however, especially on higher difficulty levels.
 * Hunter:

The Battle Rifle is not as effective against Drones, as they are extremly agile fliers and are not vulnerable to headshots. Wait for them to land on a surface, then fire at them. They can take several bursts to kill, the exact number depending on the difficulty level (e.g. it requires two bursts on Easy-Normal).
 * Drone:

Influence
The BR55 is largely based on the French standard issue FAMAS assault rifle, and also has features resembling the U.S. Army's prototype XM8 rifles. Other weapons that may have influenced its design are the SA80 and Steyr AUG because of their bull pup and scope layouts.



Appearances
The Battle Rifle was not featured in Halo 1, but was created for Halo 2, though it makes its first in-universe chronological appearance in Halo: First Strike. It was designed to replace the Pistol from the original game; this was because the developers felt that the pistol was overbalanced as compared to the other weapons in the game, and perhaps also because a rifle made more sense as a mid-range weapon than a pistol when comparing its abilities to the other weapons.

The "BR" was originally designed by Bungie to be a semi-automatic weapon, but the idea was apparently used for the Covenant Carbine instead.

Another idea the developers were working on was a three bullet minimum per burst and full auto that resulted from holding the trigger. Zoomed in, the rifle only shot a single round. However, these features were ultimately scrapped in favor of the more simplistic design that was used in the final version of Halo 2.

The Battle Rifle will be returning in Halo 3. The screenshot below shows that the "new" Battle Rifle, or BR55HB SR Battle Rifle has a longer barrel, a modified carrying handle, the scope resembles the modern-day Trijicon ACOG, and there is now a trigger guard over the trigger, a feature lacking in the Halo 2 Battle Rifle. In the Halo 3 Beta, it functioned identically to its Halo 2 iteration. However, Bungie has stated that certain weapons will be tweaked slightly between then and the time the game is released, so the BR may function somewhat differently in the final game.

Ammo
It is interesting to note the ammo used for the Battle Rifle. It uses a new 9.5mm x 40 Experimental Round. The 7.62 x 51 mm NATO round is a rather high-powered round used on the MA5B and on modern-day marksman rifles and machine guns. The 7.62 mm already has a history of having too much recoil because of the round's high power, which made it hard to fire fully-automatically in assault rifles. While the BR55's larger 9.5 mm round would be heavier and would thus presumably generate even more recoil than the 7.62 mm NATO, this is not necessarily the case. Since the Battle Rifle's rounds have a noticeably shorter case length than the 7.62 mm NATO (40 mm vs. 51 mm), they most like contain much less powder that the 7.62 mm NATO, which would yield less muzzle energy and thus less recoil, making the weapon more manageable.

However, the size of the ammo would have a problem fitting in the 36-round magazine of the current Battle Rifle. If a Heckler Koch G3 (which is chambered in 7.62mm x 51) has a standard magazine count of 20 and be the size that it is, it would be hard to see a cartridge much wider than the 7.62mm fit inside of a magazine of the Battle Rifle's size and with a capacity of 36 rounds. The Battle Rifle's magazine would have to be about twice as long as it actually is to hold that many rounds. This is a continuous pattern with UNSC assault rifles as a similar instance occurred with the MA5B. The MA5B has a magazine of 60 rounds chambered in the 7.62mm x 51 with a rather "small" magazine size, which looks to be smaller than the Battle Rifle's magazine.

Fully Loaded Battle Rifle?
On the Level Quarantine Zone (Level) in Halo 2, the player can find a Battle Rifle from a dead UNSC soldier that, when reloaded, can have a total of 236 rounds of ammo total. A few players have speculated that this is the "full" combat load for the Battle Rifle, as the player can normally carry only 108 spare rounds.

Glitches
The Battle Rifle may be used in several glitches. Although they can be used with all weapons, the BXR weapons glitch allows a user to melee, cancel the animation, and then fire, by tapping B (melee), X right afterwards, and then R (the right trigger/gun). This causes an instant kill to a shielded opponent (Elite in campaign or opponent in matchmaking).

Another glitch is the RRX, also known as the double-shot. When you press R (the right trigger)twice without pausing followed by pressing the X button right after the pressing of the second R, instead of firing a three-round burst followed by a pause, it fires six bullets without pausing, simulating automatic fire. After successfully pulling off the glitch, your weapon reloads but without any reloading animation. The drawback with the glitch originally was that once you did the double shot, you were reloading the weapon and therefore could not interrupt it and start firing the weapon again to perform another double shot. However this was solved by tapping the Y button twice to switch your weapon and to quickly switch back to your battle rifle, which interrupted the reloading procedure and you, could thus start double-shooting again. It takes four bursts from the battle rifle to the head to kill a target, so successfully tapping RRXYYRRX while accurately firing gave you the ability to kill an opponent quickly, but it is very difficult to master.

There is also the RRYB, an instant kill glitch where you press the right trigger twice, immediately followed by pressing Y (which switched to your other weapon) followed by pressing B (melee) all while running towards your target. It is essentially a BXR but in reverse and you fire two shots instead of one.

Constant fire - This glitch is not easy to perform, but not hard either. The player must not have host connection of the party else it doesn't work. First, fire one bullet of the BR, next throw a grenade straight away, and then tap reload twice or three times quickly before resuming firing, constantly. If it works you should be able to fire all your ammo without reloading. (RLXX(X)RRRR)

Trivia

 * Its reticle resembles the symbol of the Zodiac Killer.
 * On the side of the Battle Rifle, (opposite side to the bolt) there are three Chinese symbols. Some people have stated that it may mean "The Monkey King".
 * This weapon was first introduced in Eric Nylund's Halo: First Strike novel. It was noted that this rifle had "a longer barrel and stock, with a cut down muzzle shroud.", "A scope was mounted on an optics railing along the top of the rifle". Spartan 043 (Will) once commented on the rifle: "Auto zoom, nice."
 * The Battle Rifle variant in Halo 3 is called the BR55HB SR Battle Rifle. The "HB" most likely stands for "Heavy Barrel".
 * The Battle Rifle was originally named the HA871.
 * On Youtube there is a certain video of Halo 3 that shows a Battle Rifle with an M45 Grenade Launcher along with the Spiker, Sniper Rifle, and MA5C.

Character Compatibility

 * Elites
 * Spartans
 * Marines
 * Brutes (High Charity level, only on Legendary, though this is very rare.)
 * Drones (have animation but not used)
 * Jackals
 * Flood Combat Form (Human)
 * Flood Combat Form (Elite)