Guns are not difficult to make. Submachine guns are some of the easiest to construct with simple tools. Add a $100 electric welder from Harbor Freight and they become a project for a few weekends. Once the templates and jigs are produced for a small shop, they can be turned out with a few hours of labor.
Brazil has many simple homemade submachine guns showing up on its street The number found in Israel is rising. From haaretz.com:
A thin strand connects the three most recent shootings in Jerusalem. Similar to other incidents characterizing the current wave of terror, the terrorists didn’t know each other, there was no guiding hand, and there was no coordination. However, all of the attackers used the same weapon – a “Carlo,” as it’s known on the street.
It’s a homemade imitation of the Swedish-made Carl Gustav recoilless rifle, which was used primarily in the 1950s and ’60s
However, over the years, as the illegal market for standard weapons became more and more expensive – Kalashnikov and Tavor rifles can cost between 60,000 to 80,000 shekels ($15,400-$20,500) – the Carlo was improved and became more widespread. Today, almost anyone can pick up the weapon from a starting price of around 3,000 shekels, up to northward of 17,000 shekels for an especially high-quality version.