Does amputation of the barrel and stock of a Mosin make the result a bolt action pistol?
No. If the reciever was not originally a pistol there is no way to reclassify it. Theoretically you could have two identical guns, one legal, one not.
“Does amputation of the barrel and stock of a Mosin make the result a bolt action pistol?”
IANAL but I think that if it was originally a rifle with legal length barrel and you cut the barrel to under 16, it’s an SBR even if the barrel is as short as a Chief Special snubby.