I don't understand why people find Scrakes, Fleshpounds, and Sirens so scary as a non-sharpshooter.
I can kill a Scrake (level 5 commando) in about 1 clip of my SCAR (which I WILL have before they show up)
And if I can't, I just weaken to slightly over half hp, I can tell via commando perk, then use a whole clip to finish them.
For a Fleshpound I just get a safe distance, unload a full clip, reload, repeat... and it dies. (this doesn't work AS well on large games, but then you just take 2-3 shots every 5 or so seconds, or just get a teeny bit farther away and use a few rounds from a 3rd clip)
Sirens as a commando are laughable, not mentioned here, but people always complain about them.
I actually appreciate that they don't hurt my armor, keeps it nice and fresh for the big scary things. (i.e. when flesh pounds spawn behind that car next to you)
So yeah, in summary:
Step 1. Buy a SCAR.
Step 2. Weaken with half a clip to a full clip depending on what it is.
Step 3. Use a full clip to kill it.
Step 4. Gloat to your team that you just soloed a flesh pound while they got killed by gorefasts.