Did the German 3,7 cm Flak SK C/36 exist?

[Tony Williams]

and another:

3,7CM FLAK M42: 37 × 250B AMMUNITION.

This Rheinmetall-Borsig design for the Kriegsmarine was a second attempt at an automatic naval 37mm Flak cannon, following-on from the little-used SK C/36 Flak (see above) which bequeathed its ammunition and Bofors-type feed to the M42, 5-round clips being retained. The M42 was evidently closely based on the C/36, otherwise there would seem to have been no point in retaining its unique ammunition instead of using the standard 37 × 264B of the other Flak guns. The performance was similar to the Luftwaffe’s 3,7cm Flak 37 although the mechanism as well as the ammunition differed; the gun was long-recoil operated with an artillery-type wedge lock and continuous feed. An L/69 barrel was used, gun weight was 300kg and the RoF was 160–180rpm.

The original mounting for the M42 was the Flaklafette C/36 (as used by the SK C/36 cannon) but this was soon replaced by the triaxially stabilized LC/39 (also in a U-boat version) and the LM 42 and LM 43, both developed specifically for the gun and weighing 1,350kg. There was a twin mounting, the Doppellafette LM 42 (DLM 42) which weighed 1,750kg. Despite the M42 designation, the gun entered service in late 1943, initially for submarines. An installation programme for fitting this gun to smaller surface ships got underway in 1944.

 

[Tony Williams]

and finally:

3,7CM FLAK 43: 37 × 264B AMMUNITION. ALSO
KNOWN AS GERÄT 339.

This was the final successful attempt at an automatic 37mm Flak cannon, intended for use by both the land forces and the Kriegsmarine. It used the same ammunition as the earlier Flak 18, 36 and 37 series and the same L/57 barrel length, but a new gas-operated mechanism derived from that of the 3 cm MK 103 and featuring a diagonal wedge lock boosted the cyclic rate to 250rpm. Ammunition feed was from the side through enlarged trunnions to minimize the movement of the loading tray and the ammunition came in eight-round strips. Gun weight was 265kg. There were also twin-gun mountings, with the Luftwaffe Flakzwilling 43 mounting one gun above the other, while the Kriegsmarine Flak LM 44 placed them side-by-side.

 

[Tony Williams]

And while I'm at it, extracts from the ammunition section of Autocannon:


37 × 250R SK C/36 AND M42

Most German 37mm Flak automatic cannon used in World War II used the 37 × 264B ammunition described below, but two of the naval guns are exceptions. The 37 × 250R cartridge is almost identical to the German army’s 37 × 249R light tank/anti-tank round, only with a slightly thicker rim (3.9mm rather than 2.5mm – presumably to strengthen it in view of the more violent extraction forces in an automatic weapon) and a modified HEI-T projectile. The thick- rimmed round was developed for the naval Flak 3,7cm SK C/36 (cartridge cases with C/36 stamps exist); little is known about this gun, but it appears to have been officially adopted and was installed in a number of second-line vessels. The M42 inherited the same ammunition, but itself saw little use, its successor, the M43, using the standard 37 × 264B round.

The thick-rimmed cartridge case is straight tapered. The HE projectiles were the same as those in the 37 × 264B Flak. The original C/36 loading fired a 625g HE-T shell at an MV of 840m/s. The M42 loadings used 175–185g of propellant generating 290Mpa. There are two crimping grooves locating the projectiles more firmly in the case. This round used the same projectiles as the 37 × 264B except for the APCR. The complete round is 355mm long and weighed 1.37kg when loaded with the standard HEI-T projec- tile, which weighed 644g and was fired at 845m/s. There was also a 680–700g AP loading fired at 815m/s and a 550g Minengeschoss fired at 925m/s, although that last one may not have had time to get into service.

Incidentally, the German navy started the war with a different 37mm Flak gun, the SK C/30, which used very powerful 37 × 380R ammunition, but this was manually loaded so very slow-firing.

37 × 264B FLAK 18

This was the standard German land- based medium automatic AA gun ammunition of World War II, being used in a succession of weapons designated Flak 18, 36, 37 and the M43 which was also used in a naval mounting. It was also used in a modified version of the Flak 18, the BK 3,7 aircraft gun used for ground attack.

The cartridge case is tapered and belted, typical of Rheinmetall-Borsig automatic cannon ammunition of the period. It contained 189g propellant which generated 255Mpa chamber pressure. The complete round is 367mm long and weighs about 1.5kg. Projectiles had two copper driving bands until 1940 when a shortage of copper led to the use of a single soft-iron band instead, which required the gun chamber to be slightly shortened. The usual loadings were:

• HE: 635–644g nose-fuzed shell, with or without added incendiary element or tracer; HEI-T contained 24g HEI; SD (self destruct) impact fuze; MV 820m/s; 6.5 s tracer burn

• AP-T: 680–700g base-fuzed shell; 790m/s; 2 s tracer burn; penetration 50mm/90 degrees/500m, 40mm/60 degrees/500m

• APCR: (H-Panzergranate for the BK 3,7 only); 380g tungsten-cored shot, MV 1,170m/s; penetration 140mm/ 90°/100m, 70mm/60°/100m.

• In addition, a Minengeschoss was under development: 550g, contained 90g HTA explosive; the tracer burned for 2,000m (4.1 s); SD took place 2,800–3,500m.

Russia acquired technology from Rheinmetall in the early 1930s and developed a multi-purpose automatic cannon around the Flak 18 ammunition: the AKT-37. This failed to enter service.

 

[_Sarcasticat_]

And while I'm at it, extracts from the ammunition section of Autocannon:

View attachment 673479
37 × 250R SK C/36 AND M42

Most German 37mm Flak automatic cannon used in World War II used the 37 × 264B ammunition described below, but two of the naval guns are exceptions. The 37 × 250R cartridge is almost identical to the German army’s 37 × 249R light tank/anti-tank round, only with a slightly thicker rim (3.9mm rather than 2.5mm – presumably to strengthen it in view of the more violent extraction forces in an automatic weapon) and a modified HEI-T projectile. The thick- rimmed round was developed for the naval Flak 3,7cm SK C/36 (cartridge cases with C/36 stamps exist); little is known about this gun, but it appears to have been officially adopted and was installed in a number of second-line vessels. The M42 inherited the same ammunition, but itself saw little use, its successor, the M43, using the standard 37 × 264B round.

The thick-rimmed cartridge case is straight tapered. The HE projectiles were the same as those in the 37 × 264B Flak. The original C/36 loading fired a 625g HE-T shell at an MV of 840m/s. The M42 loadings used 175–185g of propellant generating 290Mpa. There are two crimping grooves locating the projectiles more firmly in the case. This round used the same projectiles as the 37 × 264B except for the APCR. The complete round is 355mm long and weighed 1.37kg when loaded with the standard HEI-T projec- tile, which weighed 644g and was fired at 845m/s. There was also a 680–700g AP loading fired at 815m/s and a 550g Minengeschoss fired at 925m/s, although that last one may not have had time to get into service.

Incidentally, the German navy started the war with a different 37mm Flak gun, the SK C/30, which used very powerful 37 × 380R ammunition, but this was manually loaded so very slow-firing.

37 × 264B FLAK 18

This was the standard German land- based medium automatic AA gun ammunition of World War II, being used in a succession of weapons designated Flak 18, 36, 37 and the M43 which was also used in a naval mounting. It was also used in a modified version of the Flak 18, the BK 3,7 aircraft gun used for ground attack.

The cartridge case is tapered and belted, typical of Rheinmetall-Borsig automatic cannon ammunition of the period. It contained 189g propellant which generated 255Mpa chamber pressure. The complete round is 367mm long and weighs about 1.5kg. Projectiles had two copper driving bands until 1940 when a shortage of copper led to the use of a single soft-iron band instead, which required the gun chamber to be slightly shortened. The usual loadings were:

• HE: 635–644g nose-fuzed shell, with or without added incendiary element or tracer; HEI-T contained 24g HEI; SD (self destruct) impact fuze; MV 820m/s; 6.5 s tracer burn

• AP-T: 680–700g base-fuzed shell; 790m/s; 2 s tracer burn; penetration 50mm/90 degrees/500m, 40mm/60 degrees/500m

• APCR: (H-Panzergranate for the BK 3,7 only); 380g tungsten-cored shot, MV 1,170m/s; penetration 140mm/ 90°/100m, 70mm/60°/100m.

• In addition, a Minengeschoss was under development: 550g, contained 90g HTA explosive; the tracer burned for 2,000m (4.1 s); SD took place 2,800–3,500m.

Russia acquired technology from Rheinmetall in the early 1930s and developed a multi-purpose automatic cannon around the Flak 18 ammunition: the AKT-37. This failed to enter service.

This is an exceptional book with a lot of great information. I will be purchasing it myself if at all possible. In the meanwhile, is there anything regarding the 3cm MK103, specifically in the Flakvierling mount?

 

[Tony Williams]

This is an exceptional book with a lot of great information. I will be purchasing it myself if at all possible. In the meanwhile, is there anything regarding the 3cm MK103, specifically in the Flakvierling mount?

The main focus of the book is on the guns and ammunition, with few details about mountings, sights etc.

The publication date is now late April. It keeps sliding...

 

[_Sarcasticat_]

This is an exceptional book with a lot of great information. I will be purchasing it myself if at all possible. In the meanwhile, is there anything regarding the 3cm MK103, specifically in the Flakvierling mount?

The main focus of the book is on the guns and ammunition, with few details about mountings, sights etc.

The publication date is now late April. It keeps sliding...

Guess that won't stop me from placing my order. Thanks for the source - if it ever comes out.