Will blanks even cycle an unmodified handgun?
Nope, and they are capable of killing at close range
Real semiautos have restrictors inserted into the barrels if they are being used in a hollywood movie and must cycle properly with blanks.
And, yes, they can kill. In the 1980s an actor named John Eric-Hexum was filming a TV series called
"Cover Up." This was before airsoft guns became common for use in TV and pre- CGI, so gun stuff was usually real guns loaded with blanks. The afore-mentioned actor, while not on set shooting, picked up a prop gun loaded with blanks that was being used in the show, and being "playfull" but not particularly smart, put the muzzle to his head and fired it. The resulting blast was enough to give John Eric-Hexum a concussion, which killed him.