A modified version of the gun designed specifically for vehicle-mounting was the 7.5 cm KwK 40, which differed primarily in using more compact ammunition, thereby allowing more rounds to be carried inside the vehicles.

However, while the Pak 38 made extensive use of light alloys to reduce overall gun weight, these were now earmarked for aircraft production to supply the Luftwaffe.

[citation needed] The Pak 40 was the standard German anti-tank gun until the end of the war, and was supplied by Germany to its allies.

A lighter version of the Pak 40 was used as the BK 7,5 automatic "weapon system" in the Henschel Hs 129B-3 and the Junkers Ju 88P-1 ground attack aircraft.

This version of the Pak 40 was the heaviest of the Bordkanone series of heavy calibre aircraft guns, incorporating a twelve-round magazine.

It was designed to fire the same low-capacity APCBC, HE and HL projectiles that had been standardized for use in the long barrelled Kampfwagenkanone KwK 40 tank-mounted guns of the mid-war and later marks of the Panzer IV medium tank.

In addition, there was an APCR shot (Panzergranate 40) for the Pak 40, a munition which - reliant on supplies of tungsten - eventually became very scarce.

[8] The main differences amongst the rounds fired by 75 mm German guns were in the length and shape of the cartridge cases as well as the primers used.

[9] Probably[citation needed] because of these results, period intelligence publications ("Handbook on German Military Forces") gave about 770 m/s as the Pak 40 APCBC muzzle velocity.

After the war, the Pak 40 remained in service in several European armies, including Albania, Bulgaria, Czechoslovakia, Finland, Norway, Hungary and Romania.

[14] Six ex-Portuguese Army Pak 40s divided into two artillery detachments were stationed in Dili during the Indonesian invasion of East Timor in 1975.