One thing I've come to realise over the last few days in matchmaking is that I'm absolutely useless with the Assault Rifle. This wasn't so much the case in past games. I'm by no means a good player, but damn, give me an Assault Rifle and I'm going to suck. Suck hard.
 
I guess it'll just be a matter of practice, I'm not sure what I'm doing wrong, but I'm guessing I'm probably holding the trigger a little too much without realising. The DMR has become far too much of a crutch for me. Anyone have any tips?

shoot until you get realy close then bop em' in the head....wait that's for Halo 3....
 
mmm....circle strafe around them until you pop the shield then move in for the smack

I used to only use the Assault Rifle because I hated the battle rifle. Now though Its either Pistol or DMR to I barely touch the AR now

" shoot until you get realy close then bop em' in the head....wait that's for Halo 3....  mmm....circle strafe around them until you pop the shield then move in for the smack "

The damage on the assault rifle is reeeealy low.  You have to hit a guy with almost a full clip to drain their shields.  I'd rather use the DMR.

Just switch to the pistol at start. Way more powerful.

I use it as if it was the BR. Burst rounds so it's more accurate, unless it's point blank range in which case I unload while trying to get closer for a melee.

When your shields go down, either throw a grenade or try for a melee kill. 

I read somewhere that you should use short burst when using the AR, but yeah, it seems kinda crazy.  The Pistol is pretty sweet.  Have much better luck with that.

" Just switch to the pistol at start. Way more powerful. "

yeah it's just not worth using the battle rifle. grab a DMR or switch to your pistol right away. the Rifle takes over a clip in most scenarios to put someone down. it's just not reasonable.

Hit Y.

I ditch the Assault rifle for the DMR the second I find one.  I usually 
ditch the pistol for a Plasma Pistol as well but so far it doesn't seem
a very effective combo like it was in the old days.

I'm pretty sure everybody sucks with the assault rifle. It's just one of those guns nobody likes and only uses if they're out of ammo for their other weapons.

I do pretty well each match I play and it's the main weapon I use.

The Assault Rifle loses accuracy as you fire it.  
 
Basically, burst fire Assault Rifle at medium to short range and unload at short range. Switch to Pistol or DMR for long to medium range and long range.