The SR9s are modified HK91-series rifles intended to qualify for import as sporting rifles after the US ban on imported assault rifles in 1989. The visible differences include the removal of the flash suppressor, bayonet lugs, and pistol grip (on the base model) in order to improve the design's acceptance as a sporting rifle. The SR9s have a medium weight barrel that is slightly less than 20 inches. Internal differences include a new buffer system and a change to polygonal rifling.
All SR9s are marked "Made in W-Germany" on the right side of the receiver. SR9s imported after September 1994 were sold with a 5-round magazine because of the US Federal ban on 'high-capacity magazines' (magazines capable of holding more than 10 rounds).
While all HKs display good accuracy, the basic SR9 does not meet the everyday standards of sniping. But the T and TC versions of the SR9 can make good sniper or designated marksman rifles.
The T is the target version of the SR9 and uses the PSG-1 trigger group with the MSG-90 adjustable stock. The rifle is tuned for better accuracy and will shoot around 1 MOA with some good ammo.
The TC version of the SR9 takes the accuracy of the T model one step further. It also comes with the fully adjustable PSG-1 stock. This is the target competition version and should be fairly accurate, maybe even sub-MOA.
- Due to the relatively low number of SR9Ts and SR9TCs imported into the United States, most of the SR9 variants appearing in Hollywood movies are actually HK91s customized to resemble SR9Ts or SR9TCs.