whats point with play BBwar ??

when play as BBwar ,how can i choose another weapons faster?? just more practice?

Im not sure what your current way of weapon swapping is, but it's (obviously) better to use the hotkeys in the first place. Secondly, you will have to cancel your next action (autoattack) before you can actually weapon swap without delay (standard being the escape key) or by sidestepping (best is to use click to move for this) after using backbreaker.

Hold control and click f1,f2, etc. Move with Q and swap at same time is another way