IMO, if you can master the HK5SD then move up to a harder challenge, the Model-18, it's a pistol so you can have it with a long or medium range primary weapon... the Model-18 only has 17 in a clip and knocks out the whole clip in about half a second, but if you're a master of the HK5 headshots, then you'll love this gun, owns everything in CQB. especially if you've got 3 or more guys in front of you, just get the head height and strafe, it's like using the Laser in Hardware Online Arena