Looking good! Here's that long piece:
A Fusion of Assault Rifle and SMG
"Assault rifles," which constitute the mainstay of man-portable military weaponry, can be said to have been introduced as rifles with an added full-auto firing feature. The problem is that rifle ammunition is relatively high-powered, so simply full-auto firing the same ammunition destroys any hope of maintaining consistently high accuracy. (In fact, several full-auto, man-portable weapons were produced that used rifle ammunition, but they all turned out to be pretty useless to all but the most heavily-built operators).
As such, the powder load was reduced, and the stock type changed to a straight stock (rifles up until this point employed a downward-curving stock to allow recoil to dissipate upwards). That is the assault rifle we know.
The lower-powered rounds of the assault rifle, then, gave it slightly less range and stopping power than its rifle forebears, but at the time, infantry was already beginning the march towards mechanisation, and pure range was no longer particularly emphasised. More importantly, the requisite battlefield movement speed had risen to an incomparable level, and this "man-portable firearm" was suddenly burdened with the essential need to be capable of area suppression in order to be considered effective at all.
Meanwhile, submachine guns (SMGs) also emerged, also as man-portable full-auto firearms. Despite significantly lacking in range and stopping power, they were praised for the simplicity of using existing handgun ammunition, and were effectively put to use in urban warfare and anti-crime roles, where larger ammunition would not be needed in combat in enclosed spaces.
However, the increased severity of urban crime and the greater power of firearms in the hands of criminals meant that situations where the SMG was insufficient were on the rise. To meet the new need, various companies developed weapons that would act as a midpoint between assault rifle and SMG. The 9-Weapon is one of those.
