hen leaving the barrel it would have been rotating at a rate approaching 200,000 RPM.
That is faster than most small vehicular turbochargers and not that far behind a dentists drill.
Not true, it you actually spin (rotate) things at 200'000 Rpm, the projectile actually becomes more unstable and is more prone to spalling (tumbling). Its been a while since I've had my hands on an AK47, but IIRC it has a uniform right hand twist in the rifling of the barrel, which causes the round to spin and come out of the barrel on the 'upwards' part of the rifling which gives the round it's elliptical trajectory and will be about 3000rpm.
I'd have to check my notes but to give you an idea, a modern artillery piece that fires out to 17km, only gives it's projectile a slow rotation speed.
AK's are renowned for their inaccuracy, (having been on the receiving end) anything over 500 meters and its hard to hit things accurately. This was mostly likely celebratory fire, or from a scoped weapon?