Editing Thompson submachine gun (section)

====M1928A1====
[[File:Halftrack-fort-knox-4.jpg|thumb|M1928A1 at [[Fort Knox, Kentucky|Fort Knox]], [[Kentucky]], June 1942]]

The M1928A1 variant entered mass production before the [[attack on Pearl Harbor]], as on-hand stocks ran out. Changes included a horizontal forend, in place of the distinctive vertical foregrip ("[[pistol grip]]"), and a provision for a military [[sling (firearms)|sling]]. Despite new U.S. contracts for Lend-Lease shipments abroad to China, France, and the United Kingdom, as well as the needs of American armed forces, only two factories supplied M1928A1 Thompsons during the early years of World War II. Though it could use both the 50-round drum and the 20- or 30-round box magazines, active service favored the box magazines as the drums were more prone to jamming, rattled when moving, and were too heavy and bulky on long patrols. 562,511 were made. Wartime production variants had a fixed rear sight without the triangular sight guard wings and a non-ribbed barrel, both like those found on the M1/M1A1.

In addition, the Soviet Union received M1928A1s, included as standard equipment with the [[M3 Stuart|M3]] [[light tank]]s obtained through Lend-Lease. These submachine guns were used to a limited extent by the Red Army.<ref>{{cite web|url=https://pamyat-naroda.ru/documents/view/?id=238922686|title = Память народа::Поиск документов частей}}</ref>

Some M1928A1 Thompsons were used by the French before and during the Battle of France (1940) under the designation "Pistolet-mitrailleur 11 mm 43 (C.45) M. 28 A1."

An M1928A1 with an unusual inline stock, modified with elevated sights to increase accuracy, also was produced. Some Thompsons were built with a folding stock, similar to [[M1A1 Carbine]]s used by Allied tank crews, drivers and paratroopers and submarine raiders.<ref>{{cite web|url=http://www.forgottenweapons.com/experimental-thompson-stock/|title=Experimental Thompson Stock|work=Forgotten Weapons|date=2012-12-07}}</ref>