Would the Madsen's 11.35mm round be a better option for the early WWII fighters?

[Jabberwocky]

There was a thread on the 11.35mm Madsen on Anthony William's Delphi forums waaaay back in 2008 (hi Tony!).

Some relevant data for the Madsen as installed on Argentina's Hawk 75s:

Gun Length: 1,280 mm (325 mm longer than the RAF's .303 Brownings)
Barrel length: 750 mm
Weight: 10.5-10.6 kg
Round weight: 19.83 g for API with steel core.
Rate of fire: 900-1,050 rpm;
Muzzle velocity: 825-880 m/sec
Recoil force: 80 kg (for reference, the Vickers .50 has 168 kg of recoil, the Oerlikon FF has 210 kg and the USAAF 37mm has a massive 771 kg of recoil)

From Tony himself:

"With a projectile weight of 20 grams and a muzzle velocity of 850 m/s, the Damage score *snip* would be 17 for the AP bullet. No Dixon incendiary was made for the round, but this obviously would have happened had it entered RAF service, and it's reasonable to assume the same 5% content by weight as the .303, giving a Damage score of 25 (rounded down) and an average score (assuming a 50:50 AP/incendiary mix) of 21, and a Power score of 2.​

​

The Madsen M1927 11.35mm gun weighed 10.5 kg and fired at 900-1,050 rpm (975 rpm average, or 16 rps). Multiplying the RoF in rps by the cartridge power gives a Gun Power rating of 32 (compared with 20 for the .303 Browning). Dividing this by the weight gives a Gun Efficiency score of 3.05, which is towards the top end of the range for MGs.​

​

What this means is that the Madsen weighed only slightly more than the .303 Browning but was more than 50% more powerful (cartridge power x RoF) and eight Madsens would therefore have been much harder-hitting for much the same installed weight. A better compromise might have been six 11.35mm. These would have delivered more power (total Power rating 192 compared with 160 for 8 x .303) for less weight (63 kg bare gun weights compared with 80 kg), allowing a greater ammunition load to be carried."​

 

[elbmc1969]

There was a thread on the 11.35mm Madsen on Anthony William's Delphi forums waaaay back in 2008 (hi Tony!).

Some relevant data for the Madsen as installed on Argentina's Hawk 75s:

Importantly, the Argentine 11.35mm Madsens were not standard Madsens. The Argentines made serious local modifications--they actually took ground-mount Madsens and adapted them to the aircraft--so the RAF would not have bought the same Madsens as those the Argentines used. (Well, I suppose they might have ...)

I don't know if the data given there was for stock Madsens. I might be able to motivate myself to check ...

 

[Spindash64]

honestly, if you're going to go thru all of the effort of shoehorning a .50 cal to use 11.35mm ammunition, you may as well save yourself the time and just use the .50 cal instead

 

[elbmc1969]

honestly, if you're going to go thru all of the effort of shoehorning a .50 cal to use 11.35mm ammunition, you may as well save yourself the time and just use the .50 cal instead

I have no idea what you're referring to.

 

[Spindash64]

sorry. earlier in the thread someone was talking about taking a .50 cal and modifying it to the 11.35mm caliber. Which, to me, seems like a rather odd way to go about it, rather than just using the .50 caliber with .50 caliber ammunition

 

[kool kitty89]

sorry. earlier in the thread someone was talking about taking a .50 cal and modifying it to the 11.35mm caliber. Which, to me, seems like a rather odd way to go about it, rather than just using the .50 caliber with .50 caliber ammunition

stoxm73 started the thread by suggesting the 11.35 mm Madsden cartridge was short enough to potentially adapt to a rifle caliber machine gun, which would be more the point of such a cartridge as it's a very small and light "heavy" machine gun cartridge, much less powerful than the .50 Vickers (12.7x80 or 12.7x81SR) though loaded to a higher velocity with a relatively light 306 grain (19.83 g) and 850 m/s.

The cartridge case is 61.81 mm long and the overall length is under 82.74 mm, compare this to 63.3 and 85 mm for .30-06.

See:

11.35x62 Madsen / MUNICION.ORG

Small Caliber Ammuntion Identification Guide DST 1160G 514 81 Vol 1 : Free Download, Borrow, and Streaming : Internet Archive

Small Caliber Ammuntion Identification Guide DST 1160G 514 81 Vol 1

archive.org

pg 62

"The 11.35x62 cartridge was designed by Dansk Industri Syndikat, a Danish firm, and developed by Kynoch, Ltd., in the United Kingdom, for use in the
11.42 mm Madsen machinegun. Although the gun never achieved widespread popularity, it was adopted by Argentina. Cartridges in this caliber were made in
the 1930s by Kynoch, and in 1940 to 1946 by Argentina.
Bullet weight is 19.83 grams and muzzle velocity, 850 m/s. Kynoch production included ball, AP, tracer, and a smoke tracer-incendiary type with a white
phosphorus filler.
Kynoch´s color coding for these types is as follows: Ball—no color tip; AP—green bullet tip; tracer—red bullet tip; and smoke tracer (WP filler)—blue tip."

In this context of a rifle caliber machine gun action length, it would be akin to the 11 mm Vickers gun of WWI (a higher pressure adaptation of the older 11 mm Gras black powder cartridge), though a good bit more powerful than that cartridge, more in the realm of the modern .458 Winchester Magnum and harder to compare to the .450 Nitro Express or similar .40~.45 caliber big game cartridges that era (1890s to 1910s) as they all loaded much heavier bullets than 300 grains at lower velocities. It's also more powerful than the high pressure .45-70 loadings using 300 grain bullets. The bullet diameter is also basically .458 caliber, though closer to .459 (still in the ".45" caliber range as the bore is likely ~.450 inches in diameter, that is the land diameter, not grooves) Though 11.35 mm would actually be about .447" bore diameter while .450 would be 11.43mm. Though the above quoted section also says 11.42 mm, which might just be a typo.

The 10.5 kg weight of the 11.35 mm Madsen machine gun is in the same weight class as the M1919M2 aircraft Browning and .303 Browning, and lighter than the MG-17 and .303 Vickers derivatives (incuding the 1930s vintage Class E Vickers used by the Japanese as the Army Type 97 and Navy Type 89). So it wouldn't be a stretch to assume the M1919 Browning mechanism could be adapted to fire the 11.35x62mm Madsen cartridge and could have been considered for directly adapting the same M1919M2 aircraft variant the British had chosen to license for .303 British. Additionally, had they chosen to avoid loading cordite in said ammunition, it could remain closed-bolt (simplifying synchronization) rather than the open bolt system of the .303 browning. (synchronization being achieved by holding the firing pin back until the synchronizing mechanism allowed its release, similar to the MG 17's functionality)

This would make more sense than getting a license for the Madsen Machine gun itself as it required some complex curved machining on at least a few parts and raised concerns with most nations that considered licensed manufacturing of any of the Madsen guns. Most of the Madsen guns are derived from the same basic long-recoil action of the Madsen Light Machine Gun of 1902 (not to be confused with the more widely used Browning Long Recoil system that tended to result in a much lower rate of fire a la Chauchat or M4 37 mm cannon, same as the semi-auto Browning shotguns and Remington autoloading rifles). The complex curves were of noted concern when the US evaluated the 23 mm Madsen cannon as well in regards to adopting it for mass production in the US. (there could be potential engineering fixes for this, like stamped or forged components with reduced machining time, but with the possible exception of the 23 mm cannon, there should've been better alternative gun designs adaptable to the 11.35 mm cartridge at lower expense, and likely with better performance, and better reliability)

The 11.35 mm Madsen cartridge itself was developed by Kynoch in the UK, so the British should've had early access to that cartridge for evaluation purposes, plus an existing manufacturing and supply base set up through Kynoch. (albeit Kynoch also produced .50 BMG ammunition throughout this period and it tended to be slightly more powerful than the equivalent US loadings of the time, though similarly lower velocity than that adopted in 1941, at about 2500 ft/s or 762 m/s, but firing an 805 grain bullet rather than 750 grains, this compared to the 570 grains of the .50 vickers)

On the note of bullet design and ballistics, the 11.35 mm round with 11.67 mm bullet diameter and 306 grain bullet weight has a much lower sectional density than either than .50 vickers or (especially) the .50 BMG, and while ballistic coefficient is also dependent on bullet shape and length, the 11.35 mm bullet is relatively stubby compared to either of the others (albeit the 12.7x81mm export ammo also tended to be stubbier and blunter than the domestic .50 Vickers rimless loadings). This all means that, while velocity is relatively high at 850 m/s, it will lose energy much faster and have a shorter effective range and less flat trajectory at long range. The lower sectional density (and lower mass) would also make it considerably weaker for armor penetration than the contemporary .50 cal and 13 mm class cartridges.

That said, the incendiary capacity should still be significantly better than any rifle caliber bullets out there and the larger bullet diameter would play a significant role there. Additionally, a huge part of the weakness in rifle caliber ammunition (ie 6.5 to 8 mm) against German aircraft during the Battle of Britain wasn't just the added armor, but use of self-sealing fuel tanks. Armor would largely protect against 20 mm explosive shells as well (the main reason the British weren't interested in lower velocity 20 mm cannons), but both high explosve shells and bullets in the .50 caliber size range could blow, tear, or punch holes into tanks too large for the sealing material to function. So the 11.35 mm projectiles would likely have been able to defeat German fuel tank protection and allow incendiary rounds to light up the leaking fuel (which would make .303 incendiary bullets a perfectly good complement to those guns or any .50 or 11~13 mm guns from this period, even ones with relatively poor armor penetration).

All of the externally self sealing fuel tanks of the sort both the British and Germans used during the Battle of Britain (sheet metal tanks with sealing material coating the outside) were vulnerable to .50 cal sized holes being punched in them, let alone larger holes caused by explosive shells (or even just .50 cal incendiary rounds), and it wasn't until the US introduced a new generation of self-sealing tanks or fuel cells specifically designed to withstand .50 cal hits, did this change. (I believe those were generally composite tanks or bladders made up of rubber or other polymer material and reinforcing materials, they weighed more and took up more space than metal tanks, hence the increase in weight and reduction in fuel capacity of the P-40C vs the earlier B, which had only used external self sealing material)







On the note of the aircraft Vickers guns, though: I've heard of their jamming issues come up quite often, but only in aircraft use while conversely being among the most stand out reliable tripod mounted ground based machine guns ever built with hundreds of thousands of rounds fired without malfunctions of any kind.

However, I haven't seen this specifically applied to all later developments of aircraft vickers guns, speaking on derivatives of the short recoil mechanism based on the original Maxim gun mechanism (so not the Vickers K). The Class E was such a derivative and, I believe, was the last of the Vickers guns in RAF service, following the Mk.V, but I'm not sure it was widely used before the .303 Browning was already entering service. I've seen references to the Gloster Gladiator being armed with Vickers Mk.V guns (and lewis guns in the wings), but I haven't seen much of anything specific on the reliability of the Mk.V or Class E as those would've been the ones around in the mid 1930s.

The Japanese Army and Navy both adopted derivatives of the Vickers Class E as their primary rifle caliber machine guns in fixed, forward firing mounts on thair aircraft, chambered in .303 British (7.7x56R) for the IJN and 7.7x58mmSR for the IJA and used them heavily in the early years of the war, albeit in synchronized nose mounts and not in wing mounts, but then again most such aircraft had no wing mounted guns (or had oerlikon 20 mm cannons in the wings, like the Zero). On top of that, the Army had the Te-1, a flexible mount version of the Vickers E, among the wide variety of other rifle caliber guns used by the Army and Navy of mixed British, Czech, German, and indigenous Japanese design.

The Army and Navy both used M2 Browning machine gun derivatives for their 12.7 and 13.2 mm guns (as well as 20, 30, and 37 mm guns in the Army), but never in 7.7 mm. All the references I've seen point to the Japanese upgrading to other guns for more firepower, not for reliability, so did they somehow manage to fix the issues with the Vickers or did Japanese not experience them for some reason, or just not find them a major hindrance? The Browning guns were significantly lighter and faster firing, so made sense to use for further development regardless of reliability compared to the Vickers.

 

[Shortround6]

A bit of a delay.

On the note of the aircraft Vickers guns, though: I've heard of their jamming issues come up quite often, but only in aircraft use while conversely being among the most stand out reliable tripod mounted ground based machine guns ever built with hundreds of thousands of rounds fired without malfunctions of any kind.

I believe somebodies advertising men are working overtime.
I have read that the Vicker's gun was subject to something like 27 possible stoppages according the manual. I have no idea if some armies counted stoppages a different than malfunctions or if malfunctions include parts breakage while a stoppage does not.
In any case most of the possible stoppages on the Vickers gun were supposed to be able to diagnosed by a good gunner who had committed the manual to memory and remembered the appropriate remedial action. Which general involved noting exactly where in it's arc the cocking lever had stopped and either giving a hefty tug either backwards or forwards while administering a healthy thump to the gun housing. If you tried to move the cocking lever the wrong way you could make things worse
The Vickers guns rarely broke any parts however and if they did, each gun was furnished with a spare "lock" or bolt assembly in the gunner's kit which could be dropped into the receiver in short order to get the firing again and an assistant gunner or the main gunner could try to fix the broken lock during a lull in the fighting. There was a least one spare firing pin and extractor in the kit (?) but it was often faster to change the assembley rather than trying to change small parts in the lock assembly while fighting.
The Vickers guns had to deal with both fabric and metal belts and wet (or frozen) fabric belts were host of problems all their own.
The Vickers guns were extremely durable and most of the time were very quick to get back into action without needing replacement parts. BUT ground guns had a sizable team to support them. The RAF did not trust them anywhere they could not administer the gloved had thump and cocking hand yank. Of course they may have still been using fabric belts in the late 20s or early 30s.

On top of that, the Army had the Te-1, a flexible mount version of the Vickers E,

Kind of a Hobson's choice or near to it. Vickers and the Japanese had gotten the type E up to 900rpm and it did have a belt. Most of the Japanese flexible machine guns were a pretty unimpressive lot. Including this

fast firing (counting both barrels) but each barrel only had 45 rounds and the mechanism was clumsy.
Also note that the flexible gunner with a Te-1 could still thump and tug on the gun

All the references I've seen point to the Japanese upgrading to other guns for more firepower, not for reliability, so did they somehow manage to fix the issues with the Vickers or did Japanese not experience them for some reason, or just not find them a major hindrance?

Please note that the Japanese navy used the same 7.7mm Vickers machine as the army but they never used it where the pilot could not reach it.
The Army did use it in the wings of some (few) early Ki-61 fighters and that is pretty much the wing mounted service history of the Vickers E type in Japanese service.