A mobile scanner gun system for processing a retail store POS sales transaction, comprising: a) a main body portion extending toward a handle portion, said main body portion having a base, side walls, a front wall and a back wall constructed to form an interior cavity, wherein said front wall includes an aperture with a lens recessed therein; b) said front wall having a trigger member located near said base of said main body; c) a USB barcode scanner mounted above and in front of said trigger, said scanner input device having two drivers, including 1) a native device driver and 2) a keyboard input driver, said scanner input device being in communication with said trigger for initiating a scan of a barcode; characterized in that d) a mobile tablet device is located above the scanner and a USB magnetic stripe reader for carrying out and processing sales transaction is located alongside a short edge of the mobile tablet device, said MSR being end to end encrypted through to the bank card authorization processor for PCI compliance requirements; e) said top wall of said main body portion having a rotating attachment means comprising a base mount universal receiver with rotational coupling means adapted to interchangeably mount and communicate through a specialized universal serial bus wiring harness with the mobile tablet device having a system integrated therein that enables store level real-time inventory management and a fully functioning POS capability for selling merchandise in a retail sales environment; f) said base mount universal receiver with rotational coupling means is adapted to rotate on the base from a vertical position to a horizontal position via 90 degree rotation on the horizontal plane without operational delay of said system. a) a main body portion extending toward a handle portion, said main body portion having a base, side walls, a front wall and a back wall constructed to form an interior cavity, wherein said front wall includes an aperture with a lens recessed therein; b) said front wall having a trigger member located near said base of said main body; c) a USB barcode scanner mounted above and in front of said trigger, said scanner input device having two drivers, including 1) a native device driver and 2) a keyboard input driver, said scanner input device being in communication with said trigger for initiating a scan of a barcode; characterized in that d) a mobile tablet device is located above the scanner and a USB magnetic stripe reader for carrying out and processing sales transaction is located alongside a short edge of the mobile tablet device, said MSR being end to end encrypted through to the bank card authorization processor for PCI compliance requirements; e) said top wall of said main body portion having a rotating attachment means comprising a base mount universal receiver with rotational coupling means adapted to interchangeably mount and communicate through a specialized universal serial bus wiring harness with the mobile tablet device having a system integrated therein that enables store level real-time inventory management and a fully functioning POS capability for selling merchandise in a retail sales environment; f) said base mount universal receiver with rotational coupling means is adapted to rotate on the base from a vertical position to a horizontal position via 90 degree rotation on the horizontal plane without operational delay of said system.