US Armor

Weren't there 2 versions of the 75mm gun, one on the M3 Lee and early Sherman models, then an upgraded version on later models?

 

You very much were, and I hope you continue. I love the knowledge you pour out in your posts, and look forward to reading them. In fact you are one of the main reasons I log on virtually every day, I'm afraid I might miss one of your posts.

 

Yes. The earlier gun was the 75mm M2, the later was the 75mm gun M3. The M2 was 31 calibres long with an MV of 1850 fs, the M3 40 calibres long with an MV of 2030 fs. Armor penetration with the M3 was about 20% better than the earlier M2, though they both fired the same ammunition. That's what I've read anyhow, though RichTO may have more.

 

One of the many persistent, but incorrect, beliefs about American Ordnance is that the 75mm tank guns developed for the Medium Tank M3 and M4 was simply the old M1897 "French 75". The truth is only the ammunition and caliber were the same; the guns were very different. From my manuscript.

"[SIZE=12pt]The stopgap Medium Tank, designated the M3, was based upon the Medium Tank T5E2, tested in 1939 as part of the Medium Tank T5 project, which mounted the 75mm howitzer.[1][/SIZE] One of the first things decided was that the 75mm howitzer, while a fine field piece, was unsuitable as a direct-fire tank weapon. The other standard 75mm field piece available they considered, the M1897 Gun – the venerable “French 75” – Ordnance judged unsuitable for various technical design reasons. Ordnance also realized that there was no time for the usual leisurely peacetime design cycle. The last tank gun developed, the 37mm Gun M5/M6 began gestation in 1921-1924 and Ordnance did not standardize it until 16 years later on 14 November 1940.[SIZE=12pt][2][/SIZE] Instead, designers elected to make use of the 75mm Gun T6, which was the latest in a series of attempts by Ordnance dating to the early 1930’s to develop an “all purpose” weapon suitable as both an antiaircraft and a field artillery gun.[SIZE=12pt][3][/SIZE] A 75mm Gun T6 was modified with a semiautomatic vertical sliding breechblock and was designated the T7, which was later standardized as the 75mm Gun M2.[SIZE=12pt][4][/SIZE] Later extended from a bore length of 84 inches to 110.63 inches with a horizontal sliding breechblock as the T8 75mm Gun, Ordnance standardized it on 24 July 1941 as the 75mm Gun M3, which became the standard armament in both the Medium Tanks M3 and M4.[SIZE=12pt][5]"[/SIZE]


[SIZE=10pt][1][/SIZE] Hunnicutt, Sherman, p. 35.


[SIZE=10pt][2][/SIZE] Catalogue of Standard Ordnance Items, Volume II, p. 195. The 37mm Gun M5 was actually standardized a year earlier for the Light Tank M2A4 and Medium Tanks M2 and M2A1.


[SIZE=10pt][3][/SIZE] The first, the 75mm T2E1 Gun and Carriage (All Purpose) had failed testing in 1933-1934, but that did not seem to deter the designers. Major George D. Shea, F.A., An Investigation of the Advisability of Further Development of the “All Purpose Gun”, with a View to its Employment Against Mechanized Forces, Aircraft, and the Usual Ground Troops, (Fort Leavenworth, Kan.: The Command and General Staff School, 1936).


[SIZE=10pt][4][/SIZE] Hunnicutt, Sherman, pp. 59-60.


[SIZE=10pt][5][/SIZE] Catalogue of Standard Ordnance Items, Volume II, p. 197.

 

At the time, a 75mm gun that fires a MV of over 2000 f/s was suitable for the enemy tanks of the same grade, Were talking Panthers and Tigers, not even close to the medium M4. Sometimes that gets lost in the argument.

 

Pleasing propaganda film on M10's introduction.
'Are you troubled by tanks?'
https://youtu.be/eXaypTAjsec

 

I'll take two. Do they provide gift wrapping, too?