When the detectives are reviewing the gun sale record, the screen says that the gun is a Ruger model SP101 revolver and that it is a "38 Special JHP" caliber firearm. JHP (jacketed hollow point) refers to a bullet design, not to a caliber. Also, while the SP101 is offered in .38 Special, it is established earlier in the episode that the ammunition used for the murder is .357 Magnum, which cannot be fired from a handgun chambered in .38 Special.