It refers to the size of the frame.
It is not a J or K frame.
The "J" frame is the Smith & Wesson small frame revolver such as the model 36 .38 special. The smallest frame, as in the model 36 Chief's Special.
Colt J frame.
J frame
About $80.
It became known as a J frame officially in 1960. If made between 1957 and 1960, it was only known for its Model 34 designation. In any event, it can be referred to as a J frame.
Freeze Frame - The J. Geils Band album - was created on 1981-10-26.
Charter Undercover .38 Special is equivalwent to the S&W J frame size.
It is a J frame.
Blued J frame vs Stainless Steel L frame J frame holds 5 L frame can hold 6 or more
A "J" frame handgun refers to the Smith & Wesson small frame revolvers such as the model 36 and to any other handguns of that size (Taurus, for example, has a virtually identical revolver) which are build on the J size frame. S&W makes K, L, N, and X frame revolvers In ascending order of size.
You can find a parts diagram for a Smith & Wesson 5-shot .38 J-frame revolver on the manufacturer's official website or by contacting their customer service. Alternatively, you may find aftermarket parts diagrams on online gun forums or websites specializing in gun parts and accessories.