BP and Weapons

Hi

How do I get the BP? Can I buy it for ZP?

And if I buy a weapon for BP and there is no time (7 days, ...) is it permanent?

AK-47 Silver permanent is.

M4A1-Silver there is no time or permanent?

lg. awus

PS: I hope this is the rigth forum for this questions, if not please place it into the rigth one. thx