I got a Beretta while open crate but I can't use it

I bought some GP crates and won a Beretta, I set it up in my bag 1, but when I go to game to try shoot it there is no Beretta at all, I keep playing with the pistol, I press Q to switch weapons there is only the pistol and knife, I press B and the Beretta still there,I switch the map several times all of them allow all weapons, and then I try to switch the Beretta from bag 1 to bag 2 but I still cant use the gun at all.
Please help me out I spent all my GP on this Beretta now I got it but I cant use it!