TedStixon

Answer: It can be fired underwater, yes, although its effective range is tiny since the water instantly slows the bullet down. It'd definitely be able to kill Jet Li as demonstrated though, since it's pushed right up against him, thus the bullets would have very little resistance from the water. Although I don't know if it'd get quite as many shots off before jamming up. There are plenty of videos of people firing them underwater, but they always only fire a single round, presumably for safety reasons. Either way, the scene is more or less realistic.

TedStixon

Answer: The AK47 is known for its simplicity and durability, with a design that is easy to use, maintain, and repair, even in harsh conditions. It can function in extreme temperatures, dusty and sandy environments, and even when it is dirty or partially submerged in water. "How far can an AK-47 shoot underwater? - Not very far. Besides having to push water out of the barrel, bullets don't go very far through water even when the bullet exits the barrel at full muzzle velocity. Bullets hitting the water travel about 3-feet before stopping."