To identify an authentic Benjamin air rifle, check two different places for identifying markers. The left side of the barrel under the bolt should bear the Benjamin company name stamped into the metal underneath a serial number. The serial number can be researched on the Crosman website to determine when and where the gun was made and verify authenticity.
The gun model number is stamped on the end of the barrel at the top of the stock with the name of the company around the outer edges of the circle. Common Benjamin air rifle model numbers include 312, 317, 310, 342, 340 and 347. Many of these air rifles are single shot with a single cartridge that uses CO2 to fire the pellet. Others are pneumatic single shot rifles that utilize a lever pump action mechanism rather than CO2 to fire pellets. Benjamin air rifles use either BB pellets, .22 caliber pellets or .177 caliber pellets.
Sheridan acquired Benjamin prior to the 1990s, creating the Benjamin Sheridan Company, which produced air rifles. This company was purchased by Crosman in 1991. All Benjamin air rifles produced after 1992 list the month and year the rifle was produced in the serial number.