AHC: alternative big automatic weapons, 1935-55

[tomo pauk]

Big, as being from 9 mm to 60 mm. For different platforms and tasks: ground- and ship-based air defence, bomber self-defence, fixed airborne for different targets (air-to-air, air-to-surface), self-propelled or not, in wings, turrets or hand-held, synchronised or not. Pre-ww2, war time, post war/Korean war. With or without help of radar.
Keep the number of designs & calibers per country as low as possible, economies of scale do apply. The earlier in service the better. Don't hesitate using foreign design, either as-is or suitably modified.

 

[Driftless]

40mm L/60 Bofors with over-the-road gun carriages in quantity for France starting by 1938, either by import or homegrown manufacture.

 

[marathag]

Madsen 23mm

before 1940, the US seemed to have plans of this supplanting the .50 in fixed and even some free mounts in bombers, and then it all went away, and the US Ordnance Department wspent the rest of the war screwing up production of 20mm Hispanos

 

[SwampTiger]

Ordnance also screwed up the mounting on the P-36/H-75 using the Madsen. It was a large, bulky gondola which slowed the aircraft substantially.

I like the case for the Madsen, 29mm base. Use this case in a MG 151 variant with 23mm or 25mm mine shell. Now you have a bomber destroyer.

 

[Driftless]

A couple of US uses for the 23mm Madsen: nose guns for the A-20's and/or B-25's. Would the shells from the 23mm have worked against the lighter armored Japanese tanks in the Pacific?

 

[marathag]

Ordnance also screwed up the mounting on the P-36/H-75 using the Madsen. It was a large, bulky gondola which slowed the aircraft substantially.

The wing was thick enough for it, but from what I could tell, didn't want to bulge anything on the airfoil side, or mount them far forward like was done on the Mustang IA., or drop them below the leading edge, like was done on the P-47

 

[marathag]

A couple of US uses for the 23mm Madsen: nose guns for the A-20's and/or B-25's. Would the shells from the 23mm have worked against the lighter armored Japanese tanks in the Pacific?

No, not much for AP capability. It was the same idea as the Minengeschoss the German later used, a drawn steel casing rather than cast to maximize available volume for high explosive

 

[tomo pauk]

Madsen 23mm
before 1940, the US seemed to have plans of this supplanting the .50 in fixed and even some free mounts in bombers, and then it all went away, and the US Ordnance Department wspent the rest of the war screwing up production of 20mm Hispanos

Going Oerlikon way avoids possible problems with too short the casing. Coupled with earlier availbility vs. French Hispano, let alone vs. British Hispano, this might lead to having 20mm cannons already in US arsenal much before the war. USA did bought license for the big Oerlikon, the FFS, albeit a bit late, and used it mostly on ships.
Oerlikon FFL or FFF might also be good choices for the RAF, meaning cannon-armed Hurricanes and Spitfires already in 1939. Going for FFL or FFF also allows for more ammo to be carried for same weight and volume alloted vs. Hispano, plus the same cannons were smaller and lighter than Hispano.

http://www.quarryhs.co.uk/OeFFL.htm

For the RAF, the Vickers 0.50in is also an option, be it in fixed or movable installation.

 

[tomo pauk]

For ze Germans:
- "MG 141" - a 15mm cannon, firing both HE and API, belt-fed, electric primed, firing from closed bolt, 800+ rpm, 750 m/s, ~25 kg, for defensive positions, as well as synchronised for fighters
- belt-fed MG FFM already for late 1939, mostly for fighters (2-3 on BF 109, 4 on Fw 190, plus night fighters)
- "MK FF30" - the belt-fed FFM scaled up for ALT 30mmx110RB ammo, 300g M-shell @ 700 m/s, 250g 'Hartkern' AP at 800 m/s, 500-550 rpm, ~60 kg, with muzzle brake, as motor cannon, outboard on Fw 190s, for jets and night fighters; 300 g HE shell @ 770-780 m/s for Flak; all for 1943
- "MK 1035" - MK 103M necked-up to 35mm (or as much as possible), 500g M-shell at 750 m/s, as motor cannon and for jets

 

[Zen9]

DACR I think was in 34mm L70 and used multiple barrels tied to MRS.3.

CFS gun was a manual 17pdr (3.3).

 

[Ramontxo]

Well I haven't been able to find it (Saturday morning...) But there is the proposed 9mm French heavy machine gun in the best possible Lutwaffe forum. Would be far more portable (for dismounted infantry) than their 13'2 mm Hotchkiss and retain quite a punch. Also In a RA wank with a fully Keynesian UK treasury they could go to Bofors and develop the 57 mm dual AA and AT gun with powered traverse and elevation using either high explosive point detonation grenades or first a tunsteng cored API shell to be substituted with a sabot one later (remember it is a wank) to be used also in their new thirty tons kestrel powered horstmann suspension cruiser tank...

 

[James Ricker]

If the US Army ordnance bureau doesn't screw up the design the .60 caliber machine gun could have entered service in 1943. The higher muzzle velocity would have improved gunnery accuracy in air-to-air combat. That would have been a disaster for the Axis air services.

 

[tomo pauk]

Germany, continued:
- much greater proliferation of 3cm Flak towed and self-propelled, and for airborne tank busting
- 3.7 cm Flak and tank-buster based on the powerul round from here

France:
- AA gun that uses 25mm anti-tank round, preferrably on Lorraine tractor
- licence produced BMG 0.50in

 

[tomo pauk]

Soviets. What to give to the ones that already have it all?
- 'baby VYa-23', or 'VYa-23 minus' - Soviets go early with medium power 23mm cartridge, 200 g shell @ 690 m/s, 600 rpm, 50 kg. Either as engine cannon, or/and as synchronised gun. Steal idea from the Germans with regard to Mine shell.
- 'baby NS-37' - again going early with medium-powerd 37mm like they used on N-37, so that it can be used as engine-cannon without the vicious recoil. 300 rpm, 735g shell @ 690 m/s, 500 g 'arrowhead' AP @ 800+ m/s, 100 kg

'muricans:
- go early on with Oerlikon for aircraft, perhaps FFL is the best choice? Make a deal with the Swiss that also includes belt feed. Should give the US reliable cannons well before Pearl Harbor. Two per fighter (fighter with one engine - V-1710, R-1830/1820) or four (one/two R-2800, 2-stage engines, two engines). One-3 on P-39/63.
- .50 BMG upped for 20mm, as a back-up for Oerlikons, also can be synchronised.
- USN adopts the Browning's 37mm AA instead of the 1.1in

 

[Driftless]

France:
- AA gun that uses 25mm anti-tank round, preferrably on Lorraine tractor

Which gun & round was better for it's primary purpose: the AA or the AT? I gather that you see the AT gun as the better all-around weapon.

'muricans:
- USN adopts the Browning's 37mm AA instead of the 1.1in

The 1.1's were too finicky for one thing. Are you seeing the 37mm's as a short term solution till the USN switches to the Bofors, or would this be the permanent (more-or-less) placement?

 

[fastmongrel]

The French 23mm Hispano HS406 from what little I have read it was the same size gun as the 20mm HS404 but fired a projectile almost twice the weight would make an close air support weapon.

The Mohlins 20m Hispano a modified Hispano MkV that fired at 1100 rpm, 4 of them would turn any aircraft into aluminium confetti.

The Vickers 3 1/2 pounder water cooled AA gun for Naval use it was supposed to be able to swap a 2 barrels for a 4 barrels POM POM mounting weighing more than a ton less per barrel.

 

[hardrada55]

9x66 MAC 1937 HMG

 

[tomo pauk]

Which gun & round was better for it's primary purpose: the AA or the AT? I gather that you see the AT gun as the better all-around weapon.

The AA gun was a better all-around wepon, IMO.
AT gun used a bit more powerful cartridge, though.

The 1.1's were too finicky for one thing. Are you seeing the 37mm's as a short term solution till the USN switches to the Bofors, or would this be the permanent (more-or-less) placement?

Bofors was a more powerful gun, for about same weight and price. So I'd still have it produced for USN as it was historically done, while in the mean time the 37mm will hold the fort. Same gun for both Army, Navy and Marines will ease up logistics, though the naval gun will need extra protection vs. salt water.

 

[Karelian]

The 40.8mm Soviet AG-2 Automatic Grenade Launcher: by end of the war, both the Germans and Western Allies had produced their own versions of the revolutionany design of Yakov Grigoryevich Taubin.

 

[Questerr]

How about the Colt-Browning .90 Cal?