Adna R. Chaffe Jr. replaces Patton.

There is also an example of an M8 Armored Car knocking out a King Tiger, but you really shouldn't rely on crews with grapefruit sized Brass Balls to knock out tanks reliably.

True, but the Arras battle illustrated the importance of training & experience over cool looking hardware, which has been repeatedly illustrated on battlefields around the world. In Korea the M4 went up against the T34, in Israli hands it opposed T54 tanks.
 
Which they did not have to do. Choosing one of the T20 series over the M4X is understandable. Less so is not starting production of a T20 variant much earlier.

The US had enough production facilities, there was really no reason that the M4, M4X and the T2* couldn't have all done at the same time

Type Factory Dates Number Produced
M4 (Sherman I) M4 5 U.S. Factories Jul 1942 – Jan 1944 6748
M4(105): (Sherman Ib) M4(105) Chrysler Detroit Tank Arsenal Feb 1943 – Mar 1945 1641
M4A1: (Sherman II) M4A1 4 U.S. Factories Feb 1942 – Jan 1944 6821
M4A1(76): (Sherman II) M4A1(76) Pressed Steel Car Company Jan 1944 – Jun 1945 3426
M4A2: (Sherman III) M4A2 4 U.S. Factories Apr 1942 – Jun 1944 7513
M4A2(76)W: M4A2(76)W 2 U.S. Factories Jun 1944 – Jun 1945 2915
M4A3: Sherman IV M4A3 Ford Motor Company Jun 1943 – Sep 1944 1690
M4A3(75)W: M4A3(75)W Fisher, Grand Blanc Arsenal Feb 1944 – Mar 1945 3071
M4A3(76)W: M4A3(76)W 2 U.S. Factories Mar 1944 – Apr 1945 4542
M4A3(105): M4A3(105) Chrysler Detroit Tank Arsenal Jun 1944 – Jun 1945 3039
M4A3E2: M4A3E2 Fisher, Grand Blanc Arsenal May 1944 – Jul 1944 254
M4A4: (Sherman V) M4A4 Chrysler Detroit Tank Arsenal Jul 1942 – Sep 1943 7499
M4A6: M4A6 Chrysler Detroit Tank Arsenal Oct 1943 – Feb 1944 75
Grand Total: 49,234

M4 builders

American Locomotive Company
Baldwin Locomotive Works
Federal Machine and Welder Company
Lima Locomotive Works
Pressed Steel Car Company
Pacific Car and Foundry Company
Pullman Standard Car Company

As the Big Three got their large plants running, the RR Companies were sidelined, to where only Baldwin, ALCO and PSC were still building M4s
 
Which they did not have to do. Choosing one of the T20 series over the M4X is understandable. Less so is not starting production of a T20 variant much earlier.
The T20 had trouble meeting the reliability standards required by the Ordnance department. The heavier tanks were pushing the limits of transmission technology of the time. the 30-35 ton weight of the M4 was in the sweet spot for mechanical reliability. Funny thing was the heavier tanks that did not meet American reliability standards exceeded the reliability of almost every other nation.
 
The T20 had trouble meeting the reliability standards required by the Ordnance department. The heavier tanks were pushing the limits of transmission technology of the time. the 30-35 ton weight of the M4 was in the sweet spot for mechanical reliability. Funny thing was the heavier tanks that did not meet American reliability standards exceeded the reliability of almost every other nation.

The T20 basic prototype weighed in at 32.88 short tons. The M4 started at 30 tons & the late versions came in at 38 tones. Was equipped with the same GAN V-8 as the M4, & a hydraulic transmission. Was equipped with the 76mm M1 cannon and the same turret that carried that gun on the M4. Also had the HVSS suspension. The T20E3 prototype had torsion bar suspension.

A E1 version was started for a 75mm autoloading cannon. Field trials indicated a 20 RPM - Canceled. A E2 version was designated for a 3" gun as in the M10 TD, that was completed as the E3 with the 76mm M1 cannon.

T22 had the manual transmission, HVSS suspension, & turret from the T20E2. Canceled. Weight was similar to the T20.

T23 Electric drive & VVS. Weight slightly greater than the T20. First prototype of the series completed and started in tests in 1943. 'Limited production of 250 tanks authorized in May 1943. Used the T80 turret & M1 76mm gun also on the M4. A E3 variant had torsion bar suspension, which was found to reduce group pressure significantly. A E4 version with HVSS was started and canceled

T21 Light tank. Same hull/chassis form as T20, but with thinner armor in sides and front. Canceled before completed.

M27 was a proposal for a new medium tank based on the best features of the T20, T22, T23 tanks. Rejected by AGF as unneeded in favor of continuing M4 production.

T25 Weighed in at 35 tons dry. Hull was derived from the T23 modification of the T20. Speced to carry the M3 90mm gun. Original with torsion bar suspension. A E1 variant with HVSS built. Approx forty built.

T26 Weight of over 40 short tons dry from extra side & front armor. Torsion bar suspension, hydraulic transmission, M3 90mm gun.

The US had enough production facilities, there was really no reason that the M4, M4X and the T2* couldn't have all done at the same time

Type Factory Dates Number Produced
M4 (Sherman I) M4 5 U.S. Factories Jul 1942 – Jan 1944 6748
M4(105): (Sherman Ib) M4(105) Chrysler Detroit Tank Arsenal Feb 1943 – Mar 1945 1641
M4A1: (Sherman II) M4A1 4 U.S. Factories Feb 1942 – Jan 1944 6821
M4A1(76): (Sherman II) M4A1(76) Pressed Steel Car Company Jan 1944 – Jun 1945 3426
M4A2: (Sherman III) M4A2 4 U.S. Factories Apr 1942 – Jun 1944 7513
M4A2(76)W: M4A2(76)W 2 U.S. Factories Jun 1944 – Jun 1945 2915
M4A3: Sherman IV M4A3 Ford Motor Company Jun 1943 – Sep 1944 1690
M4A3(75)W: M4A3(75)W Fisher, Grand Blanc Arsenal Feb 1944 – Mar 1945 3071
M4A3(76)W: M4A3(76)W 2 U.S. Factories Mar 1944 – Apr 1945 4542
M4A3(105): M4A3(105) Chrysler Detroit Tank Arsenal Jun 1944 – Jun 1945 3039
M4A3E2: M4A3E2 Fisher, Grand Blanc Arsenal May 1944 – Jul 1944 254
M4A4: (Sherman V) M4A4 Chrysler Detroit Tank Arsenal Jul 1942 – Sep 1943 7499
M4A6: M4A6 Chrysler Detroit Tank Arsenal Oct 1943 – Feb 1944 75
Grand Total: 49,234

M4 builders

American Locomotive Company
Baldwin Locomotive Works
Federal Machine and Welder Company
Lima Locomotive Works
Pressed Steel Car Company
Pacific Car and Foundry Company
Pullman Standard Car Company

As the Big Three got their large plants running, the RR Companies were sidelined, to where only Baldwin, ALCO and PSC were still building M4s

The T23 being near complete in prototype testing in mid 1943 suggests Some sort of M2* tank could have been replacing the M4 in the ETO from early 1944. If a 90mm gun version is wanted for 1945 thats possible. But I'd prefer the 105mm short gun myself ;) Could have that in 1944.
 
True, but the Arras battle illustrated the importance of training & experience over cool looking hardware, which has been repeatedly illustrated on battlefields around the world. In Korea the M4 went up against the T34, in Israli hands it opposed T54 tanks.

Simply put, Logistics matters.
 
The T20 basic prototype weighed in at 32.88 short tons. The M4 started at 30 tons & the late versions came in at 38 tones. Was equipped with the same GAN V-8 as the M4, & a hydraulic transmission. Was equipped with the 76mm M1 cannon and the same turret that carried that gun on the M4. Also had the HVSS suspension. The T20E3 prototype had torsion bar suspension.

A E1 version was started for a 75mm autoloading cannon. Field trials indicated a 20 RPM - Canceled. A E2 version was designated for a 3" gun as in the M10 TD, that was completed as the E3 with the 76mm M1 cannon.

T22 had the manual transmission, HVSS suspension, & turret from the T20E2. Canceled. Weight was similar to the T20.

T23 Electric drive & VVS. Weight slightly greater than the T20. First prototype of the series completed and started in tests in 1943. 'Limited production of 250 tanks authorized in May 1943. Used the T80 turret & M1 76mm gun also on the M4. A E3 variant had torsion bar suspension, which was found to reduce group pressure significantly. A E4 version with HVSS was started and canceled

T21 Light tank. Same hull/chassis form as T20, but with thinner armor in sides and front. Canceled before completed.

M27 was a proposal for a new medium tank based on the best features of the T20, T22, T23 tanks. Rejected by AGF as unneeded in favor of continuing M4 production.

T25 Weighed in at 35 tons dry. Hull was derived from the T23 modification of the T20. Speced to carry the M3 90mm gun. Original with torsion bar suspension. A E1 variant with HVSS built. Approx forty built.

T26 Weight of over 40 short tons dry from extra side & front armor. Torsion bar suspension, hydraulic transmission, M3 90mm gun.



The T23 being near complete in prototype testing in mid 1943 suggests Some sort of M2* tank could have been replacing the M4 in the ETO from early 1944. If a 90mm gun version is wanted for 1945 thats possible. But I'd prefer the 105mm short gun myself ;) Could have that in 1944.
I think you have an unrealistic concept of how long it takes to layout a production facility, the warehousing and parts flow and the preproduction of components in volume. Then you actually have to build the first set of production jigs and do early runs to work out problems in the process. That also involves shutting down an existing production line and losing the production for a period of time . Then you have to ship the vehicles overseas, train the users and maintainers in their use as well as stock adequate spare parts and supplies. That all takes time and diverts away from the effort to build up adequate supplies for the invasion. It is the logistics end that staffs study and plan campaigns on.
 
I think you have an unrealistic concept of how long it takes to layout a production facility.....

I did manufacturing for some years before returning to construction.

For the T20/22/23 the one major component that was unique was the hull. The turret for the M1 76mm gun went into bulk production for the M4, the motor was already in bulk production. One can go over the list in detail but a large portion of the parts were common to the M4 & related vehicles.

Note that over 30,000 changes were documented for the M4 series. Somehow a adaquate number of those were built despite adding cast super structure, assorted turret reworks, adding a series with diesel engines, ect... ect... ect... Maybe the kraftwerke school of manufacturing will have trouble with that, but General Motors less so.
 
I think you have an unrealistic concept of how long it takes to layout a production facility, the warehousing and parts flow and the preproduction of components in volume.
Many of the early M4 producers, like Lima Locomotive Works, was due to stop Sherman production by end of 1943. They had all the facilities needed to do any tank smaller than a Locomotive.

Since early M4A1 with 75mm were not ideal forn the battlefield, anytime in late 1942 could have retooled for one of the T-2*, like the T-20E3 as M27B1 for Spring 1943 production, and this would only reduce overall Sherman numbers by a few hundred, and there was slack in other factories to have made up the difference.
Or have Lima make Jumbos from 1943 till end of war, all the ADs wanted as many as they could get, but Fisher only made 254 over a few months.
 
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