USAAF 0.60-caliber Machine Gun????

[Pioneer]

G'day gents

I am currently reading Experimental & Prototype USAF Jet Fighters - by DennisR. Jenkins & Tony R. Landis!

Whilst reading the section about the Bell XP-83 (D-16 Stratoshere Fighter), it makes mention of being designed to take a new 0.60-calibrer Heavy Machine Gun!
Does anyone have any information on this machine gun - designation, technical data etc.....?


Regards
Pioneer

 

[TomS]

This would probably be the T17, a USAAF gun based on the German MG151. It fired a .60-caliber (15.2mm x 114mm) round originally developed for a high-power antitank rifle.


Here's a synopsis of the development, with some tech specs mixed in.


http://ww2.rediscov.com/spring/VFPCGI.exe?IDCFile=/spring/DETAILS.IDC,SPECIFIC=11411,DATABASE=objects,


There was also a T58, which was basically a developed T17 with an externally-powered feeder.


http://ww2.rediscov.com/spring/VFPCGI.exe?IDCFile=/spring/DETAILS.IDC,SPECIFIC=11475,DATABASE=objects,

 

[Steve Pace]

The second of two XP-83 airplanes - of which I've never seen a picture of, was to be armed with this mg for firing tests at Wright Field but I don't have any other info on this. -SP

 

[Pioneer]

Thank you gentlemen!!

You have greatly helped answer my curiosity

15.2mm would have had a bit more hitting power than the Browning M2 12.7mm MG.

I still find it somewhat amazing just how much influence the German's had on U.S weapons research!
As a user of the M60 GPMG (which was designed from the influence of the German MG-42) and the German MG-3 GPMG, I can not but help notice the U.S. trend of overcomplicating a good weapon. I think the U.S. has been unable to appreciate the notion of 'If its not broken, then don't touch it!'

Regards
Pioneer

 

[beachhead1973]

I have seen pics as well of an M41-based quad AA systme with what appear to be Browning-derived .60-cals, deffinately not an Mg151 OR Mg213 dervivative.

Wasn't this the same round tested in the Vulcan prototypes as well?

 

[TomS]

Came across a drawing of the XP-83 nose showing the extension required for the .60-caliber guns.

I'd post it here, but I'm not sure of its legal status, so here's a link:

http://www.ww2aircraft.net/forum/weapons-systems-tech/usaaf-us-navy-guns-since-1930-a-17022-3.html

 

[TomS]

Also, I'd forgotten that the first batch of modern Gatling guns (the T45) were chambered for the same .60-caliber round. The 20mm M50 round adopted for the T171 and M61 used basically the same brass, slightly shortened and with the mouth widened. (There was also a 27mm version that must have been pretty much straight-sided.)

http://ww2.rediscov.com/spring/VFPCGI.exe?IDCFile=/spring/DETAILS.IDC,SPECIFIC=15205,DATABASE=objects,

 

[Madurai]

I have seen pics as well of an M41-based quad AA systme with what appear to be Browning-derived .60-cals, deffinately not an Mg151 OR Mg213 dervivative.

Wasn't this the same round tested in the Vulcan prototypes as well?

The Machinegun Motor Carriage T100, which is I think what you're talking about, was based on the M56 Scorpion chassis, not the M41 Bulldog.

 

[TomS]

Do you have any pictures or additional info on the T100? I'm interested in the concept, but can't find any information online aside from the designation.

 

[beachhead1973]

I have seen pics as well of an M41-based quad AA systme with what appear to be Browning-derived .60-cals, deffinately not an Mg151 OR Mg213 dervivative.

Wasn't this the same round tested in the Vulcan prototypes as well?

The Machinegun Motor Carriage T100, which is I think what you're talking about, was based on the M56 Scorpion chassis, not the M41 Bulldog.

Nope, it was deffinately an M41 or M24 derivative, with a turret looking like an advanced M45 series, possibly remote-controlled and not the six-gun M24 .50 mount either.

 

[Madurai]

Do you have any pictures or additional info on the T100? I'm interested in the concept, but can't find any information online aside from the designation.

Actually, I'm wrong (again). The T100 was based on the T37 prototype of the M41 after all. There was a separate project to mount the Stinger quad .60 turret on the M56 chassis. The Scorpion-based one I have only the most primitive line drawing for, but the T100 has a photo in Hunnicutt's Sheridan.

 

[masher47]

Steve Pace had me proof read his last book “The Big Book of X Bombers and X Fighters” in which he published the photo of the second prototype thanks to Jenkins passing it to Tailspin Turtle as shown above (in XP-83 thread) in 2011. I wrote the 1981 Airpower article and the original color cutaway (XP-83 thread) was returned to the owner back in the ‘80s’ so we only have access to what was published. Second prototype armed with two .60 cal mg.

 

[Tony Williams]

Also, I'd forgotten that the first batch of modern Gatling guns (the T45) were chambered for the same .60-caliber round. The 20mm M50 round adopted for the T171 and M61 used basically the same brass, slightly shortened and with the mouth widened. (There was also a 27mm version that must have been pretty much straight-sided.)

This is an extract from a forthcoming book of mine on automatic cannon and their ammunition:

The history of this (20 x 102) cartridge goes back to WW2 when a very powerful .60 inch anti-tank rifle was developed. This never saw service but the 15.2 x 114 ammunition was used in various experimental aircraft guns developed during WW2, notably the T17 which was a modified Mauser MG 151 but also the T18 which was a modified Hispano. After the war the .60 cartridge remained the USAAF's preferred basis for new aircraft guns, and the first versions of what became the M39 (revolver) and the M61 (rotary) were chambered for it. However, the advantages of explosive shells were finally accepted by the USAF so the case was necked out to 20 mm and slightly shortened to keep the overall length the same.

 

[Colonial-Marine]

Hi Tony, do you know if the US Army ever took a second look at the .60 caliber cartridge for use in a large heavy machine gun? Perhaps as a response to the proliferation of the Soviet 14.5mm KPV?

As for airborne use were there any particular reasons holding the T17 or T18 back from field trials overseas during WWII?

 

[Tony Williams]

When the US Army wanted something more powerful than the .50 BMG, they went to 20 mm with the Hispano Suiza HS 820 (US designation M139), in 20 x 139 calibre, which is appreciably more powerful than the usual US 20 x 102. They obviously felt that a bigger step up in power was more worthwhile.

 

[Tony Williams]

As for airborne use were there any particular reasons holding the T17 or T18 back from field trials overseas during WWII?

Probably that they never worked well enough. The US went through a bad patch in auto cannon design capabilities between the death of John Browning and "Gatling revival" of the 1950s.

 

[Magi]

The T160/M39 cannon had a .60 caliber version, the T130/M38

TM 9-213A

 

[Ravinoff]

Hi Tony, do you know if the US Army ever took a second look at the .60 caliber cartridge for use in a large heavy machine gun? Perhaps as a response to the proliferation of the Soviet 14.5mm KPV?

Kinda. I'm not sure it was ever officially tested by the US Army, but FN Herstal developed the BRG-15 starting in 1983, as a possible replacement for the M2 .50BMG. Used a 15.5x106mm cartridge in a fairly conventional gas-operated and weighed around 130lbs unloaded without mounts. Most unique feature was the dual-feed mechanism that allowed loading two belts at once with a switch to toggle between the left and right feed (which could be different ammo, or just extending the available supply).

A 15.5x106 round (bottom) compared to a standard .50BMG:


Two views of the dual-feed mechanism, empty casings would have been ejected out the bottom:

 

[Tony Williams]

The FN BRG's mechanism had soft-recoil characteristics, which made it possible to replace the .50 BMG, using the same mountings. The attraction of such a design was that the arms limitation agreements between NATO and the Warsaw Pact placed limits on light AFVs with 20+mm calibre guns, but not on on those with smaller-calibre guns. FN were unlucky with the timing; the end of the Cold War finished it.

As a matter of interest, the FN 15.5 x 106 cartridge case was based on the Russian 14.5 x 114 KPV's, just necked-out a bit (and brass rather than steel).

With the benefit of hindsight. FN should maybe have made the gun in 14.5 x 114, but designed it to use new high-pressure loadings of the ammunition with longer projectiles to boost the performance. That way, the BRG could use the cheap Russian ammo, but the KPV wouldn't have been able to use the FN ammo...

 

[Iron Felix]

With the benefit of hindsight. FN should maybe have made the gun in 14.5 x 114, but designed it to use new high-pressure loadings of the ammunition with longer projectiles to boost the performance. That way, the BRG could use the cheap Russian ammo, but the KPV wouldn't have been able to use the FN ammo...

KPV based on V-23 automatic cannon, with 23x115 cartridge (to 45 KiloJoules), and Russians use it, to built 23 mm automatic cannon for vehicles:


Only a few details differ, and if FN makes special cartridges, the Russians will easily rebuilt their KPV. And, 23 mm KPV variant - old project, stopped in 1980th and restarted today.

 

[Grey Havoc]

What was old is new again...

 

[Tony Williams]

KPV based on V-23 automatic cannon, with 23x115 cartridge (to 45 KiloJoules), and Russians use it, to built 23 mm automatic cannon for vehicles:

View attachment 632238

Felix, can you tell me where the above photo came from? I would like to use it in a book (with copyright permission and proper acknowledgements). The last I heard the 23 mm KPVB had not been adopted - has its status changed?

 

[Abingdon]

Here's the .60 cal anti-tank rifle and a close-up of the associated ammunition and clip.

 

[Abingdon]

This has nothing to do with the .60 cal project, but is a lesser known 1.1 inch/28mm cannon being developed by the US Army prior to WWII. I don't know much about the project, I just stumbled into some photos at NARA while looking for other stuff.

 

[Tony Williams]

This has nothing to do with the .60 cal project, but is a lesser known 1.1 inch/28mm cannon being developed by the US Army prior to WWII. I don't know much about the project, I just stumbled into some photos at NARA while looking for other stuff.

Well, the only 1.1 inch gun used anywhere was the USN AA gun (28 x 199SR ammo). Do you have any more info on this army gun, I've never heard of it.

 

[Iron Felix]

Felix, can you tell me where the above photo came from?

Пулемёты 6

Опытняк наземной стрелковки СССР/РФ. страница 7 - Guns.ru Talks

forum.guns.ru

 

[Abingdon]

I have a few more photos of the gun from an Ordnance collection at NARA/Still Photos dealing with testing at APG. There are no reports in the record group, only photos. Presumably there are the associated reports in the Ordnance files in the main (document) research room. But the Ordnance collection does not have good finding aids. I was mainly looking for photos of the various US Army anti-tank rifle tests in this period and stumbled into this gun while doing that.

 

[A36Apache]

if you want to know more about .60 cal developments, volume III of George M. Chinn’s “Machine Gun“ is your place to go. Pdfs of it too can be found online too.

 

[A36Apache]

I am curious however if anyone has any more information on T58 besides what can be found on the Springfield Armory link posted by TomS and what can be found in the Machine Gun Volume III by George M. Chinn (posted below).

 

[pathology_doc]

I think the U.S. has been unable to appreciate the notion of 'If its not broken, then don't touch it!'

They did eventually realize that the real answer had been sitting around since the 1890s: https://www.scribd.com/document/14173249/US-Patent-502185-Gatling-Gun-Electric

Patented by the man himself, for 3000 rounds a minute. Imagine sticking one of those in the nose of a P-38...

 

[Rickshaw]

T100 Machine Gun Carriage: