USAAF 0.60" Cannon
- Thread starter Zipper730
- Start date
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Shortround6
Major General
It offered high velocity which meant a short time of flight which meant easier gunnery.
- Thread starter
- #3
Why not just go with the 20mm? The USN and RAF were fine with it
wuzak
Captain
NIH?
Niceoldguy58
Airman
- 94
- Mar 2, 2010
I have suspected for some time that wuzak's "NIH" comment was the central issue on U.S. 20mm development for aircraft. The U.S. Army - and thus the USAAC/AAF - had a near-unholy love of the 37mm gun. Virtually every attack/ground support aircraft under development immediately prior to and during WWII had the 37mm cannon as part of of its potential armament. In many cases it was one of a number of different armament fitments. I have a copy of an original engineering drawing for mounting the 37mm in the Wing of the Mustang, probably for the A-36 or early Mustangs (sorry...can't immediately recall for which).
Nearly all American heavy bombers had 37mm turrets as part of their early design studies, and the AAF did studies for bomber mountings of cannon up to 105mm. I believe it as Oldsmobile that actually had a working prototype for a 105mm short-barreled cannon for mounting on heavy attack aircraft, and the A--26 had one mounted in a gondola in their initial proposal documents.
I suspect that this love of the 37mm gun may have had something to do with John Browning's involvement with the design of the 37mm cannon, but that is speculation on my part at this point. Browning's development of the .30 and .50 cal machine guns certainly gave him very high standing in the eyes of the command structure.
I'm considering offering a talk on U.S. gun and cannon development and mountings in WWII for the 2019 IPMS/USA contest. It has a lot of elements of "What the f... were they thinking?" in it. Let me know what you think about that idea.
AlanG
Nearly all American heavy bombers had 37mm turrets as part of their early design studies, and the AAF did studies for bomber mountings of cannon up to 105mm. I believe it as Oldsmobile that actually had a working prototype for a 105mm short-barreled cannon for mounting on heavy attack aircraft, and the A--26 had one mounted in a gondola in their initial proposal documents.
I suspect that this love of the 37mm gun may have had something to do with John Browning's involvement with the design of the 37mm cannon, but that is speculation on my part at this point. Browning's development of the .30 and .50 cal machine guns certainly gave him very high standing in the eyes of the command structure.
I'm considering offering a talk on U.S. gun and cannon development and mountings in WWII for the 2019 IPMS/USA contest. It has a lot of elements of "What the f... were they thinking?" in it. Let me know what you think about that idea.
AlanG
Shortround6
Major General
If you are not aware of it (and you might be well aware of it) there is a lot of information in "The Machine Gun" by George M. Chinn. Most of it is technical and historical but the only in the sense of what was done when, there is very little "why" (what were they thinking).
The 5 volume set is available online for download or just browsing from several sites.
The 5 volume set is available online for download or just browsing from several sites.
There is a slight chance that I may miss the IPMS/USA contest of 2019
37mm featured highly in USAAC/AAF plans due to perceived need for the fighters to kill bombers that might attack CONUS.
BTW - if there is a chance to post the picture of proposal for the 37mm aboard the P-51/A-36, I'd be glad to see it.
Shortround6
Major General
A short article on the .60 cal is here.
The American Cal. .60 Anti-Tank Rifle, T1 & T1E1 | WeaponsMan
The round and AT gun date to 1939?, the aircraft guns are somewhat later but still WW II for development.
The American Cal. .60 Anti-Tank Rifle, T1 & T1E1 | WeaponsMan
The round and AT gun date to 1939?, the aircraft guns are somewhat later but still WW II for development.
- Thread starter
- #9
Then, why was the USN okay with it?
Fascinating, did he develop a 25mm as well?
Do it!
Shortround6
Major General
In one of Anthony Williams books he states
"US research indicated that reducing the time of flight by one third would quadruple the hit probability, because most pilots seriously underestimated the amount of lead required in deflection shooting."
Designing a cartridge and bullet to achieve high velocity was not that hard, making the gun small and light while both durable and reliable was the just about insurmountable challenge as it would require advances in both propellent technology and in metallurgy.
"US research indicated that reducing the time of flight by one third would quadruple the hit probability, because most pilots seriously underestimated the amount of lead required in deflection shooting."
Designing a cartridge and bullet to achieve high velocity was not that hard, making the gun small and light while both durable and reliable was the just about insurmountable challenge as it would require advances in both propellent technology and in metallurgy.
special ed
1st Sergeant
- 4,858
- May 13, 2018
Didn't the navy use .60s along the edge of carriers as AA late in the war?
special ed
1st Sergeant
- 4,858
- May 13, 2018
Refer to Picture of the day post 1579. The mockup and original drawings for what became the B-36 shows retractable turrets with 37mm. At that time the B-36 was planned in case Britain fell and we needed to bomb across the Atlantic. So the idea of slow firing 37s for defense against fighters shows the AAF preference for 37mm for more than coastal defense.
Shortround6
Major General
It doesn't seem likely, some guns were built but appear to have been quite troublesome. It was an Army project so it seems unlikely the navy would have gotten any of the limited production guns (the were "T" series). The gun also weighed about 135lbs (at least the T17 series) and offered no real advantage in weight over the standard 20mm Oerlikon guns.
special ed
1st Sergeant
- 4,858
- May 13, 2018
I have seen video of AA fire during attacks on carriers and there is some sort of thin barreled rapid fire flexible mount weapon mounted in a horizontal line operated by a gunner.
Shortround6
Major General
These are 20mm Oerlikon guns. Are thy the same as the video?
This was the USN 1.1 in AA gun
and was just about out of service at the end of the war. While used a lot early in the war it was replaced by the 40mm Bofors gun on more important ships as supplies allowed.
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special ed
1st Sergeant
- 4,858
- May 13, 2018
It was the 1.1 I remembered. Thanks
vikingBerserker
Lieutenant General
Ahh, the Chicago Piano.
Interestingly enough, the M61 Vulcan cannon was developed in .60 (along with 20mm & 27mm).
Interestingly enough, the M61 Vulcan cannon was developed in .60 (along with 20mm & 27mm).
- Thread starter
- #18
If I recall it originally started as a 0.60 in 1946, was tested first in 1949. By around 1952 if I recall, they realized they needed to build up to 20mm or bigger.
G
gomwolf
Guest
AFAIK, first US aerial 60cal gun is T17 and it is the copied gun of German MG151/15. So... IMO, 60cal was begun, when they tried copying 15mm gun with imperial unit.
You can find futher information about in this link.
Springfield Armory Museum - Collection Record,
You can find futher information about in this link.
Springfield Armory Museum - Collection Record,
The why is easy; jet propulsion. Nazi's were flying faster aircraft and that meant actual ballistic efficiency times were becoming very short. The Air Corp needed something that launches a heavier bullet at faster speeds to extend target coverage time, deliver greater damage with the heavier bullet, and when the bullet is loaded this explosives a single hit might actually bring about a downed enemy jet.
The problems with this new round was that it used the current 20mm case and just necked it down to 15mm. Results weren't as important as the safety concerns brought about with someone loading up a 20mm cannon with 15mm ammo. After several months of consideration and thousands of rounds fired for effect, the decision was made to improve existing 20mm armaments and shelve the concept of a .60" machine gun.
