Halo 3

Battle Rifle

This is a great weapon. The bullets are fairly powerful, and with the three
shot bursts it can be devastating. A great weapon for clearing out jackals,
especially those damned snipers.

On legendary, if an enemy sniper spots you, you will probably have no more
than 2 seconds at the very most to react. If you can peek out of a corner with
your scope set in the general direction of the Jackal, one quick burst should
at the very least injure him, giving you the chance to set your sights for the
kill.

There is no single fire for the Battle Rifle. I believe it is to make the
Carbine more useful. Otherwise, I doubt many people would take much notice of
it.

36 rounds per clip. 2x Zoom.

SMG

In game, it is known as the SMG. For those [few] of you who don't know, this
stands for Sub-Machine Gun. This weapon is, in my opinion, the best for Drones.

On legendary, I very rarely used it for anything more than Drone and Grunt
cleanup. Every now and then, it served well against a single Elite. If a
tricky Elite is hiding in a corner, and you have no available grenades, this
weapon is just screaming for it. Peek around the corner with two of these and
BAM! No more Elite, lots more purple paint. It can be a bit risky though, so I
tend to stick with Plasmas for Elites.

60 rounds per clip. Dual Wield.

Shotgun

This is a weaker version of the original. It's still a great Flood stopper,
but Elites won't go down as easily with it. It used to stun them when hit by a
point blank shell. Now, it'll damage then, but it definitely won't stun them
long enough for a clean kill.

12 rounds per clip.