Would be nice if the game offer to have option to test every weapon out side of the match. I do like that at least you can play for specific time with any weapon. But it cost in-game free currency. If you'd like to try out several Assault Rifles, for example I have to spend more than a single weapon price in order to do that in a match. And still there is a cases where won't give me the best way to test weapon only in matches.
My suggestions is to have some sort of very simple level, where you can enter at any time from the lobby with any weapons. The level should have simply several targets on different range. Would be nice if some of they are moving. Or with some sort other attributes.
For reference I think everyone knows other games where they have that feature. For example the Gun Smith in Ghost Recon Future Soldiers. Other game featuring Firing Range was Ghost In The Stand Alone Complex and Ghost Recon Phantoms.
Here is a video of testing weapon in Ghost In The Shell