When the bazooka was born, it combined two cutting-edge technologies: the rocket and the shaped-charge warhead.
When the US sent bazookas to its comrades on the eastern front, they fell into German hands.
The Panzerschreck was a bazooka, scaled up to 88 mm — a successful caliber for the Germans. The earlier Panzerfaust though was something different: a cheap, single-shot, “recoilless rifle” — in the same family as the modern M3 Carl Gustaf, the Goose. So, the Panzerfaust did use a shaped-charge warhead, which could penetrate armor even at low velocity, but it didn’t use a rocket to propel it. In fact, it used 830 grains of black powder.
In movies, the modern RPG is often depicted traveling at low speed, when in real life its gunpowder booster charge launches it out of the barrel at 115 m/s, and then its rocket engine kicks it up to 295 m/s (660 mph). The original Panzerfaust actually did travel at thrown-ball speeds though: 30 m/s (67 mph).