Essentially, a PCC is a shoulder-mounted long gun that is chambered in a pistol calibre cartridge. Most long guns are traditionally chambered in dedicated rifle rounds. The PCC platform is of a similar size but chambered in a cartridge that is generally more limited, ballistically.

The first thing to understand is that the PCC is not a rifle. Even the more powerful handgun cartridges will not perform as a rifle does. Not only do they lack the same power, but they will not have the range and accuracy. However, the barrel length on these guns, usually 16 inches or more, gives most handgun cartridges a significant boost in performance. A 9mm coming out of a 16-inch barrel is producing more energy than out of a 4-inch pistol barrel. If we look at the carbines chambered in traditional revolver cartridges such as 357 or 44 magnum, we see an exponential gain in energy. 357 magnum from a rifle barrel performs more akin to a rifle than a handgun, though it is range limited due to the difference in ballistic coefficient between typical pistol and rifle bullet design.