It's a PCC faceoff episode for Classic Firearms and it's either a choice between direct blowback and roller-delayed blowback, using the Grand Power Stribog SP9A1 and SP9A3 models. The direct blowback system is simpler, more reliable, and more affordable, while the roller-delayed blowback system provides a "softer" shooting feel and less gas blowback, especially when using a suppressor.