The U.S.-made Thompson Submachine Gun was developed by Gen. John T. Thompson, who envisioned a "one-man, hand-held machine gun" in .45 ACP for use in the ongoing trench warfare of World War I. But the war ended before prototypes could be shipped to Europe. At the start of World War II, the Thompson was the only submachine gun commercially available to the Allies. But the guns were expensive to make. Savage and Auto-Ornance simplified the gun inside and out and made it cheaper and faster to make. The result was the M1 and later the M1A1 Thompson. It turns out the "Blish principle of metallic adhesion" didn't really matter.
To learn more about the iconic Thompson M1A1 Submachine Gun, watch this "I Have This Old Gun" segment from a recent episode of American Rifleman TV.