You're very close, it's a Colt .22LR. The mob used to apparently use .22LR revolvers for their hits due to the fact that they were more quiet than a 9mm when fired either under someone's jaw or behind their ear and there was also no exit wound for the bullet, making hits super quiet and not nearly as messy as the movies make them.

I can understand that. It is pretty similar to "debauchery" as a word lol.