Possible research project: What can an examiner looking at a pristine
22 caliber 40 grain R6 bullet WITHOUT any slippage marks say about what possible type of gun fired it.
Years ago I read (where???) that a bullet has to "jump" from the cylinder to the revolver's barrel, leaving slippage marks. Versus a bullet that is nearly touching the rifling in a semiautomatic pistol.
The project would entail gathering a host of 22 LR firearms (revolvers, semiautos, derringers), recovering test bullets and determining if this concept has any basis.
This project was submitted by Evan Thompson. Thank you Evan!!