.50x110mm?


#1

Anyone heard of a US experimental project where a 20x110mm case was necked down to use .50" projectiles? I recently saw one at a small gun shop near here. The story was that it was an attempt to get a flatter shooting cartridge for the M-61 “Vulcan” gatling gun. Since there is a test range nearby where G.E. used to fire these guns, it makes sense that a stray cartridge found it’s way into a local gun shop collection. The shop owner is a strange guy, so I was unable to look at the cartridge or get a headstamp.

AKMS


#2

AKMS,

There was a Cal. .50 High Velocity round made by Frankford Arsenal based on the 20x110mm Hispano-Suiza case in the 1940’s for various high velocity tests. The headstamp you didn’t get to see may have been “[case mfg.] [date] 50 HV”. I have seen some at auction with funky experimental projectiles including one with pre-engraved rotating band.

There was also .50/.60 cal. based on the .60 cal. (later 20mm) case that could have been used in early rotary gun tests.

Dave


#3

Thanks for that info. I got the impression from the gun shop guy that this was a more recent project, like the 1980’s or thereabouts. Now that I think more about it, the parent case was a 20x102mm from the M-61 Vulcan, not a 20x110mm HS. The projectile appeared to be a regular .50 Browning ball, no tip colors. Maybe the next time I get up that way I should try to get a better look at it…

AKMS


#4

There was a nice .60/.50 Cal. posted by DK on the BST board a while back. viewtopic.php?f=11&t=7454

Dave


#5

In the 1980s (and before) there was a concern with the low muzzle velocity of the M-61 which gave it a limited engagement envelop. I know of a number of initiatives to look at higher velocity air-to-air weapon for fighters. I would not be surprised to learn that they relooked at the .50x110 but I have not heard that before.

Cheers,

Lew


#6

The 20x102 (20 Vulcan) is a descendant of the .60 caliber cartridge. The .60 was an attempt to improved the ballistics, particularly air-air, of the .50 caliber, while also developing an Antitank cartridge. The .50 wasn’t fast enough, didn’t carry enough payload for air to air engagements which were now involving fast jets. The .60 was developed and had some small success, but was quickly necked up to take a 20mm projectile, for even more payload, which we know today as the 20x102. The .60 case was essentially the same as the 20 Vulcan, except for bullet diameter. The US Navy, in the 1980’s did some experimentation at China Lake with the 20 Vulcan case necked to .50 caliber.

As mentioned the 20x110 case was also necked, during WW2, to take a .50 and was known as the .50 HV project.

And, also in the late 40’s/early 50’s, the 60 case was necked down to take the .50 bullet. Several projectile variations were tried.


#7

A slight correction on the timing…the .60 cartridge was first developed for an anti-tank rifle (a tripod-mounted gas-operated semi-auto), but then was used as the basis for various WW2 aircraft MG experiments. The most successful was the T17 which was a modified version of the Mauser MG 151. About 300 were built, but never used.

Postwar, the .60 remained the basis for aircraft gun developments and the prototypes of both the M39 revolver cannon and the M61 rotary were chambered in .60 (the .60 version of the M39 was actually assigned its own designation - the M38). Before any reached the production stage, a decision was taken to neck the case out to 20mm because the much greater destructive effect of HEI cannon shells was considered worth losing some velocity to achieve.

The USN adopted a different version of the 20mm cartridge in the MK11 and MK12 cannon; the case was extended from 102mm to 110mm.


#8

Hi DaveE,

Just wondering how much the .50HV’s you’ve seen went for?. How often do you see them?.

Thanks.

Hi Tony btw.


#9

sim115,

Welcome to the Forum!

Went and dug out the auction catalog that had the .50 HV rounds with interesting projectiles I recalled. From Engel’s Auction #5 May 2003:

Item #138- Headstamp “CAL…50 T23 B [cross] F.A.50” 20mm/50, brass case, no primer, steel bullet.
Est. $100-125. Sold for $160.
The projectile is similar to that in Fig. 224 on pg. 240 of HWS II.

Item #139- Headstamp “raised B in diamond 43 50 HV” 20mm/50, Bridgeport Brass co., brass case & primer w/3, no powder, loose black steel bullet.
Est. $50-75. Sold for $85.
The projectile is similar to that in Fig. 225C on pg. 241 of HWS II.

I recall seeing at least one other with the 50 HV headstamp and a conventional .50 cal. projectile but don’t recall when or what it was going for (other than it was beyond by budget!).

Dave


#10

Perhaps I should not poke my nose in here but here is my opinion. These are the cartridges that I have in my collection that are about 50 cal and “about” 110mm.

  1. A true 50x110mm, or more accuratly 12.7x110 French XPL. It was always thought that this case type was only used for velocity tests but then some appeared with machine gun links so a weapon seems to have been developed for it. Known without headstamp and with “20 MM LUM-1-79”. Based on the Hispano Suiza case.
  2. The 50 HV based on the 20mm Hispano case, the case length here is more like 120mm & has been well described above.
  3. One of the many experimentals of the 60 cal being necked down to 50 cal. Case length is 114mm.
  4. the British .50 cal Vicker D and D*, case length 120mm.
  5. Another one that could be the 50x110mm, the 50 North or Colt-Kynoch machine gun experimental. This case length is also 110mm.

Regards

Will


20mm/50cal ID help
#11

Will,

Very nice selection to complement the thread. Thank you!

Dave


#12

I have a 15x110mm case, converted from 20x110mm Hispano, headstamped: 20x110 HIS FNB 80. Could this be part of the experiments leading to the Belgian 15x115mm cartridge?

gravelbelly


#13

Here is a picture of the USN 12.7x118 that 50m2hb mentions. It is the top item. It has a steel case with zinc chromate(?) finish. The lower case is the standard brass cased .60/.50.

Gravelbelly - Yes, your 15x110 case is one of the prototype FN rounds. Here is a picture of a few 15 x 110 AP, Short Range, weighted Drill, and 2 cases – the last being a fired pressure test.

Note the difference in rim bevels. The early rounds, characterized by the unaltered headstamp, have a very steep bevel and lack of primer crimp and seals. The later rounds, characterized by the altered headstamp have a much less pronounced bevel and a slightly thicker rim. As far as I know, these are the only 2 headstamp variations to be found and that there are no rounds with a ’15 x 110’ headstamped.

Paul


#14

Hi DaveE,

Thank you!. Thanks also for the info, would love to add one to the collection.

Will & PaulSmith, thanks for the very interesting photos!.


#15

Way off the original topic here, but I thought I’d post this picture of the 12.7x110 French machine gun round that Will referenced above. The solid aluminum drill round shows considerable abuse. The brass case was fired in a gun with a fluted chamber. It also has an indexing notch in the rim. And finally, the link. The link is marked ‘MAT-24K’ on one side and ‘500 83’ on the other (on the forward parts)

Paul


#16

Paul, the link looks much like the one for the 20x102 M39 gun and also for the 20x139 (…gun - forgot designation).


#17

I confirm, this type of link is used on the cannon of 20mm F2 by French Navy (GIAT M693).
netmarine.net/f/armes/20f2/index.htm


#18

Thank you EOD and PierreJean - I will assume that the 20mm gun system would have been modified to 12.7mm. It does makes sense to use an existing platform (and links) to conduct the test.

Paul


#19

I apologize for bringing this thread back from the dead, but I have a question about the link pictured below. Paul; are you certain that this link was original to the 12.7x110 cartridge? The reason I ask is because of its similarity to the M12 link used for 20x102 cannons. I have a small quantity of M12 links already, but I picked up some more links today at the gun shop that already had 20x102 in them. The only reason I picked up some more is because these new links aren’t marked “M-12” like my others. These new links are marked “MAT-24K” like yours, and “7-80” in white letters on the side.

Is “MAT-24K” the model number or something else? I’m just trying trying to identify these new links and what they’re used for. For reference, here’s an M-12 link on the left with the “MAT-24K” link on the right:

Another view:

And one more:

I have a feeling that they either might both be “M12” links and only some were marked as such. Also, maybe “MAT-24K” might be a manufacturer’s mark?

-WRM

[quote=“PaulSmith”]Way off the original topic here, but I thought I’d post this picture of the 12.7x110 French machine gun round that Will referenced above. The solid aluminum drill round shows considerable abuse. The brass case was fired in a gun with a fluted chamber. It also has an indexing notch in the rim. And finally, the link. The link is marked ‘MAT-24K’ on one side and ‘500 83’ on the other (on the forward parts)

[/quote]


#20

Hello,

Only one single French 20M621 weapon in caliber 20x102 has been modified at the Manufacture d’Armes de Tulle (MAT) to fire the 12.7x110.

Cheers,

JFL