caption: the terms of other factors
exif: {"Image DocumentName": "Other Factors Perfect matches sometimes difficult b/c:", "Image ImageDescription": "Presence of grit & rust in a barrel. Recovered bullets too mutilated or distorted on impact. A spent bullet\u2019s weight can sometimes determine the gun make. Microgrooves: 8-24 grooves; it\u2019s not as common. General Rifling Characteristics File. FBI database of known land/groove width for all weapons.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}