The SP5K-PDW is semi-automatic civilian sporting version of the ultimate close quarters weapon. It features a roller-delayed blowback operating system, which is legendary for its accuracy, reliability, and smooth shooting dynamic. But no matter the size, all SP5 and MP5 models share the same HK roller-delayed blowback operating system, which is legendary for its accuracy, reliability, and smooth shooting dynamic. Originally perfected on the Heckler & Koch G3 rifle, this system has been used on many HK firearms still deployed around the world. The SP5K-PDW was designed and manufactured to meet the definition of a civilian pistol. It is loaded with authentic features, like a 4.5" barrel with Navy-style threaded tri-lug adaptor, paddle magazine release, and fluted chamber.