In CoD MW2 Why can't I get A Nuke?

Okay I prestidged 3 time on my xbox 360, and it really angers me that my 2 younger bros one who is 20 who aftre months just got his first Nuke and my 16 yr old bro who keeps track of his nukes and has like 23 are able to get them and i’m not, I’ve gotten close, but then somebody always shoots me or my Chopper Gunner Down before I get there. Are there any Specific Maps That probably are best to get nukes from, or maybe it’s my perks? or maybe I just can’t do it but maybe some advice could help me with future sucess with it.

Oh and BTW here’s what I have and use.
BTW I need to level up again but here’s what I use when I’m 60 and up and all perks are Pro
One Man Army
Stopping Power
Commando
(Final Stand)
Using a ACR with Launcher or FMJ
then switch Classes into my Hardline Set which is
Scavenger
Hardline
Steady Aim
(Final Stand)
with an ACR Grenade Launcher
a AA12 with FMJ’s or Grip
Syntex Grenade

or I use my Explosive class

Scavenger
Danger Close
Commando or Steady Aim
(Final Stand)

And for Killsteaks, Harrier, Chopper Gunner and Nuke.
So why is it difficult to get a Nuke on Domination or Sabatogue?