Im currently using the ACR which is the best HC assault rifle. It's minimum damage is 30 so its always 1 hit kill no matter how far the enemy is, only other weapons to have this ability are snipers, LMGs, and the MK14. I use impact on it so enemies behind cover are taken out easily. For attachment I switch between silencer if im playing more agressive, and ACOG or hybrid sight if im feeling more campy.

My secondary is an MP9, I rarely pull it out and use it just for its 75% sprint bonus.

Leathal: Claymore, Tactical: Smoke.

Perks: Extreme conditioning, Assassin, Dead Silence.

I only play hardcore search and destroy so my setup is best for that game mode. If i am playing something else or dont feel like going try hard I change the ACR for a SPAS-12 or AA-12 with range.

Any gun with Silencer

Stinger

Sticky Grenade

Trophy System

Blind Eye

Assassin

Dead Silence

UAV/Preditor Missle/Airstrike

-On HC, most players use Blind Eye so its best to use KS that you can control.

-On Smaller Maps like Dome and Hardhat, Recon is so wonderful.

-Be aware of Ballistic Vest on HC. Just keep shooting until they are dead. Don't just assume 2 bullets and run away.

-Always be moving! Campers will get eaten by Noobtubes. With dead silence on, you will sneak up on quite a few campers and get easy kills.