When to use Secondary Weapon

When do i soppose to use my secondary weapon, im thinking about a shotgun, or a michine pistol. When do i use the weapons? i wanna get kills with my secondary weapon so i could unlock more shyt, but i be lost on when to use my secondary becuase i constantly use my primary gun.

Just wing it.

my favourite game type has to be team death match because you have got more change of getting the kill streak rewards search and destroy pisses me off

i always use the AA12 and every time im inside a building or map with lots of corners and tight spots i bring it out, then i use primary weapon when im not so confined.

i now use Akimbo PP2000 with FMJ. This is a beast set-up. You can also cancel out FMJ wit Extended Magz. this is great for clearing house

i now like runnin around with a Desert Eagle with a Tactical knife. Im new to this so im not REALLY an expert @ it, but the few times i used it, it was nice