The ones still in existence are Mauser, JP Sauer/SIG Sauer, Steyr, and Brno. All the others have either gone bankrupt or were dissolved after the war. In most cases, not much is known about what happened to the engineers, but a good amount is known about the executives. In most cases, the assets of the companies were seized and either re-organized or liquidated.

Post-WW2, Mauser-Oberndorf was occupied by the French in order to provide arms to the reformed French military, which was severely under equipped. The French manufactured ~51,000 K98ks before dismantling the factory in June of 1946 for the purpose of war reparations. About 60% of the facility was destroyed in the process as were the records from the war. 3 former Mauser engineers, Edmund Heckler, Theodor Koch, and Alex Seidel, salvaged what they could and formed Heckler and Koch. After WW2, Mauser mainly focused on precision measurement instruments before returning to the firearms industry with mainly hunting and sporting rifles. In 1994, they were acquired by Rheinmetall.

Erma-Werke had an interesting history post-WW2. Berthold Giepel, the founder of Erma in 1922 after WW1, was arrested and imprisoned by the Allies. He underwent denazification and was eventually released. Since the Thurgia region fell into the Soviet occupation zone, Erma-Werke's assets were liquidated in 1948 under order of Marshal Zhukov. It was reformed in 1949 by Giepel in the Dachau region, near Munich. It mainly focused on household appliances. In 1952, it won a contract to supply German police forces with parts, primarily for the M1 carbine. After the Bundeswehr was reformed in 1955, Erma unsuccessfully bid to provide a new sub-machine gun to the both the Bundeswehr and police forces, ultimately losing out to the Uzi. They would again lose the next sub-machine gun contract to the Walther MP and would eventually go bankrupt. They were eventually taken over by Merkel Jagd- und Sportwaffen, a division of Steyr-Mannlicher, in the 1990s. The firearms were still sold under the Erma name. In 2004, H&K took over the company and ceased production of products under the Erma name. Giepel and his son, who was the Chief Engineer in the post-war era, left the company after it was acquired by Merkel.

JP Sauer is still in existence largely as 2 entities, Sauer und Sohn in Germany and the famous partnership with SIG, resulting in SIG Sauer. Since the Suhl region fell into the the Soviet Occupation Zone, Sauer's assets were seized. Sauer was merged with Merkel, Greifelt, Haenel, and Ernst Thalmann and merged into VEB-Ernst-Thalmann-Werke-Suhl in the 1970s. Ersnt Thalmann is known for making SKS rifles, Makarov pistols, and AK-47/AKM/AK-74, and the Wieger StG 940. Rolf Sauer sold the rights to a western company in the 1950s, resulting in 2 JP Sauer und Sohn companies. They partnered with SIG in 1976, resulting in the now famous SIG-Sauer P220. After the fall of the Berlin Wall and collapse of the East German government, the West German government closed the Suhl factory in 1990, ending the existence of 2 Sauer entities, leaving only the western one.

Steyr had a very turbulent history after WW2. After the Anschluss, Steyr-Daimler-Puch AG (SDP) was rolled into Reichswerke Hermann Goring. During the Nazi era, Steyr was run by Georg Meindl, a prominent SS party member. Many Steyr workers had socialist/communist leanings and were arrested and sent to the newly formed camp system. In March of 1943, Steyr and the SS drew up a contract, exchanging inmate labor at Gusen for rifles. After the liberation of SDP, Meindl was arrested, but later released, after which he would commit suicide. Goring was captured and tried, but committed suicide before he could be executed. SDP would make tractors and automobiles post-war, with Steyr eventually being sold to Steyr-Mannlicher, selling weapons in the current era such as the AUG.

CZ Brno and Bystrica were both repatriated to the Czechoslovakians after WW2. From 1945-1948, CZ Brno was slowly nationalized in preparation of the Communist takeover in 1948. CZ Bystrica ended K98k production in 1945, eventually shifting to non-weapon production in 1955. When Czechoslovakia was annexed in 1939, it was folded into Reichswerke Hermann Goring, like Steyr. Dr. Wolf was appointed director and the managers and personnel were largely unchanged.

Berlin-Lubecker Maschinenfabrik(BLM) was formed in 1936, along with Berlin-Suhler-Waffen und Fahrzeugwekre (BSW). BLM was founded by Bernhard Berghaus. In August, 1944, BLM was bombed and severely damaged. BLM had used forced labor throughout the war, but had also invented several techniques and machinery for barrel straightening, cold hammer forging, swaging of barrels into receivers, and sight alignment (I'm not using these achievements as an excuse for forced labor. It will play into Berghaus' future). In the last days of the war, Berghaus fled Germany to Switzerland. British and French forces demanded his extradition on the grounds of his use of forced labor and his status within the Nazi party. Both Switzerland and the Allies were interested in his patents for the achievements developed during the war. However, he was never convicted and in 1948, a Lubeck court certified Berghaus' denazification. He died in 1966 in Switzerland.

BSW was formed in 1936. Fritz Sauckel, a Nazi party officer and extreme anti-Semite, launched a 14-month investigation into Simson & Co, a Jewish-owned German weapons manufacturer who had secured contracts with the Allies after WW1 for arming the German military. Arthur Simson and a few top executives were indicted on corruption. Simson would sign his company over in exchange for his freedom in 1935. BSW/Gustloff would use forced labor during the course of the war. After the war, Fritz Sauckel was captured and tried at Nuremburg. He was found guilty of war crimes and crimes against humanity and executed.