Explain weapons on Battlefield 3 (PS3)?

[TheStedman]

Been playing Battlefield 3 online for a while now. Got a pretty good understanding of everything, but was curious about how the weapons are available and not.

Can someone explain to me how the weapons are available to one team, but not the other? Like, I have seen one weapon that is "unlocked" selcted, but it tells me that it can't be saved (I think it said something about not being available to that team; US or the other guys). Is one side only allowed to use certain weapons the whole time? For example, is the US allowed to use the M16A3, but the other guys are not allowed to? Or will the weapon be unlocked for BOTH sides at some point?

I also noticed that my primary weapon tends to change whenever the game changes what team I am playing on (US or the other guys). Like, in my Assualt kit, I have the M16A3 that I play with when I am on the US team. However, when I end up getting switched to the other guys, the primary weapon is changed to one of the Ak-47 weapons (if I remember correctly). Either way, it changes and then it will change back when I go back to being on the US side.

The answer with the most explanation of how things work will get the best answer. Thanks!

 

[ANNiE]

Each gun either belongs to the US or Russian(not sure) or both. You can't use a US gun with the other team. It is like a real war. You don't see Iraq using the guns we use.