Question: What German intermediate cartridge rifle/carbine is known under the designations MP 43 and MP 44?

Context articles: 6.5×50mmSR Arisaka
.45-90 Sharps
7.92×33mm Kurz
StG 45(M)
Assault rifle
6.8mm Remington SPC
5.45×39mm
5.8×42mm
StG 44
Intermediate cartridge

The 6.5×50mm Semi-Rimmed (6.5×50mmSR) Japanese cartridge, currently manufactured under the designation "6.5mm Jap", was adopted by the Imperial Japanese Army in 1897, along with the Type 30 Arisaka infantry rifle and carbine.
 The new rifle and cartridge replaced the 8×52mm Murata round used in the Type 22 Murata Rifle.
 In 1902 the Imperial Japanese Navy chambered its Type 35 rifle for the cartridge as well.
 In 1905, the round also came to be offered in the Type 38 Arisaka infantry rifle and carbine, both of which rendered the Type 30 obsolete in Imperial Army service.
 Type 44 cavalry carbines, first adopted in 1911, were also chambered in 6.5×50mm.
The .45-90 Sharps cartridge is a black powder round introduced in 1877 by the Sharps Rifle Manufacturing Company.
 Also known as the .45 2 4/10, the cartridge was developed for hunting and long range target shooting.
 In the modern day, it is used for Black Powder Cartridge Rifle competitions.
The 7.92×33mm "Kurz (designated as the 7.92 x 33 kurz by the C.I.P.) is a rimless bottlenecked intermediate rifle cartridge developed in Nazi Germany prior to and during World War II.
 The ammunition is also referred to as 7.9mm "Kurz ("German: "Kurz" " meaning "short"), 7.9 "Kurz", or 7.9mmK, or 8×33 Polte.
 It was specifically intended for development of an automatic carbine (assault rifle).
 The round was developed as a compromise between the longer 7.92×57mm rifle and the 9×19mm Parabellum pistol rounds, and is known as an intermediate cartridge (German: "Mittelpatrone" ).
The StG 45(M) ('Sturmgewehr 45' literally "storm rifle" or "assault rifle 1945") sometimes referred to as the MP 45(M), was a prototype assault rifle developed by Mauser for the "Wehrmacht" at the end of World War II, using an innovative roller-delayed blowback operating system.
 It fired the 7.92×33mm Kurz (or "Pistolenpatrone 7.9mm") intermediate cartridge at a cyclic rate of around 450 rounds per minute.
An assault rifle is a selective-fire rifle that uses an intermediate cartridge and a detachable magazine.
 Assault rifles were first used during World War II.
 Though Western nations were slow to accept the assault rifle concept, by the end of the 20th century they had become the standard weapon in most of the world's armies, replacing full-powered rifles and sub-machine guns in most roles.
 Examples include the StG 44, AK-47 and the M16 rifle.
The 6.8 mm Remington Special Purpose Cartridge (6.8 SPC, 6.8 SPC II or 6.8×43mm) is a rimless bottlenecked intermediate rifle cartridge that was developed by Remington Arms in collaboration with members of the U.S. Army Marksmanship Unit, United States Special Operations Command to possibly replace the 5.56 NATO cartridge in a Short Barreled Rifle(SBR)/Carbine.
The 5.45×39mm cartridge is a rimless bottlenecked Intermediate cartridge.
 It was introduced into service in 1974 by the Soviet Union for use with the new AK-74 assault rifle.
 The 5.45×39mm gradually supplemented, then largely replaced the 7.62×39mm cartridge in Soviet and Warsaw Pact service as their primary military service rifle cartridge.
The 5.8×42mm / DBP87 ("Dàn (弹) Bùqiāng (步枪) Pŭtòng (普通), 1987"; literally "Standard Rifle Cartridge, 1987") is a military rimless bottlenecked intermediate cartridge developed in the People's Republic of China.
 There is limited information on this cartridge, although the People's Liberation Army says that it is superior to the 5.56×45mm NATO and 5.45×39mm Soviet cartridges.
 Another variant called the DBP88 “heavy round” was designed specifically for squad automatic weapons and designated marksman rifles.
 The 5.8×42mm “heavy round” cartridge has the same dimensions as the standard 5.8×42mm cartridge, but utilizes a longer streamlined bullet with a heavy steel core for increased performance at extended ranges and penetration.
 As of 2010 all 5.8×42mm cartridge variants are gradually succeeded by the DBP10 variant.
The StG 44 (abbreviation of Sturmgewehr 44, "assault rifle 44") is a German selective-fire rifle developed during World War II.
 It is also known under the designations MP 43 and MP 44 ("Maschinenpistole 43", "Maschinenpistole 44" respectively).
An intermediate cartridge is a rifle/carbine cartridge that is less powerful than typical full-power battle rifle cartridges, such as the .303 British, 7.62×54mmR, 7.92×57mm Mauser, .30-06 Springfield or 7.62×51mm NATO, but still has significantly longer effective range than pistol cartridges.
 As their recoil is significantly reduced compared to high power rifle cartridges, fully automatic rifles firing intermediate cartridges are relatively easy to control.
 However, even though less powerful than a traditional full-power rifle cartridge, the ballistics are still sufficient for an effective range of 250 – , which are the maximum typical engagement ranges in modern combat.
 This allowed for the development of the assault rifle, a selective fire weapon that is more compact and lighter than rifles that fire full power cartridges.
 The first intermediate cartridge to see widespread service was the German 7.92×33mm Kurz used in the StG 44.
 Other notable examples include the Soviet 7.62×39mm used in the AK-47 and AKM series, 5.45x39mm first used in the AK-74, and the American 5.56×45mm NATO cartridge first used in the M16.