As the overconfident bounty hunter Greedo continued to babble on with his threats, under the table Han Solo slowly pulled his blaster from it's holster...
Han Solo's blaster in this closeup at the Mos Eisley Cantina was made to take the place of the original blaster during filming of additional footage in Hollywood. This had to be done because none of the real converted firearm props were brought back from England. In the absence of the original firing prop this version was made from a replica German "Broomhandle" Mauser pistol manufactured by the Model Gun Corporation of Japan.
1896 German "Broomhandle" Mauser Replica from MGC (Model Gun Corporation)
The scope was a Super 2 1/2X model manufactured in Japan by the sporting goods company Compac. It was mounted to the scope bracket with two Weaver "football" style scope rings.
Compac Super 2 1/2X
An electronic heat sink was added as the front grill.
The flash suppressor on this blaster was from a M3 Grease Gun. During filming the flash suppressor was removed, presumably so it would not get caught in the holster as it was being pulled out.
M3 Grease Gun with Flash Suppressor