火箭筒拿反了,炮口对着后面开了一炮.怎么准确翻译

“火箭筒拿反了, 炮口对着后面开了一炮”
The bazooka was held in the wrong direction, and a shot was fired from behind.

就这样～

是 bazooka还是 RPG= Rocket Propelled Grenade(火箭助推榴弹）?

The rocket launcher makes things difficult for sb. on the contrary the gun muzzle has opened one cannon to back