The Call of Duty games use 3074 for acquiring open NAT type to their games. However, when another instance of the game whether that's from a games console or PC, the second instance of the game won't be able to connect to the server on the same port as NAT is 1:1.
From reading on the internet Call of Duty uses the UDP ports range 3070-3080. This means that if UDP 3074 is already occupied on the first console, in theory the second instance of the game should be able to open up a port on the next available one in its range.
I have put this to the test but it's backfiring badly giving me strict NAT on one of my consoles.
These are steps I have taken and I can reproduce this every time:-
If I turn on my PlayStation 3 games console, load up a Call of Duty game and connect to multiplayer I have open NAT type
If I look at the Active UPnP Redirects list I can see my PS3's LAN IP address assigned to UDP 3074 under the Client Port and External Port
If I turn on my PlayStation 4 games console, load up a different Call of Duty game and connect to multiplayer I'm presented with strict NAT type
If I look at the Active UPnP Redirects list the second time round I can see my PS4's LAN IP address assigned UDP to 3074 under Client Port but under External Port it shows as UDP 307*
Here's the screenshot of the PS4 jumping to UDP 3191 but internally connected to UDP 3074