[Chasaway]

"...That is some ricochet...."

I know, right? But a direct shot at 10 feet makes less sense, at least fitting the evidence. C

[Red Steel]

There’s some else to consider. A light powder loaded cartridge that reduced velocity.

[5th MEB]

Angle of the ricochet seems kind of acute, at least at the ranges your giving.
Penetrating wound from a straight shot should be a round puncture; if the bullet was a ricochet the wound should be keyholed or at least pretty distorted, pathologist should be able to tell you that.
You might try contacting some of the ballistics experts on military bases in your area, or even their Corpsmen or Medics. They aren’t experts and probably couldn’t testify, but they have seen an awful lot of these types of holes in both materials and flesh (unfortunately).
They could probably direct you to some real experts.