sentences:  Because the two cartridges, the .50 BMG and .416 Barrett, have identical base dimensions, all that is needed to convert a rifle to use one or the other cartridge is a relatively quick barrel swap.The Barrett Model 99 was initially the only commercially available rifle using the cartridge.In 2009, Zel Custom Manufacturing released the Tactilite .416 Barrett upper for AR-style rifles Zel Custom Manufacturing curtailed operations in 2018 which was subsumed by another manufacturer, McCutchen Firearms, after the BATFE classified barreled upper assemblies in .50 caliber to be firearms in and of themselves on July 17, 2018 .