Chieftain Talks M4 Sherman & 76mm

[Music] greetings all since it seems to be a topic which comes up from time to time i thought a quick video on history of up gunning the m4 medium tank might be in order there are a number of common misconceptions going around which i have addressed in other videos such as the idea that us's tanks were not supposed to engage other tanks and that's why the sherman did not come with a 76 millimeter until late in the war indeed there is an opinion that the us introduced 76 millimeter only after the initial fighting it normally saw the 75 millimeter is wanting although technically true this ladder position is often used to imply that the 76 millimeter was developed and installed onto the m4 only as a reaction to the german tanks as opposed to having been something developed long before they were encountered the history of the 76 millimeter gun on the m4 medium is an excellent example of the process lag in between somebody coming up with a good idea and actually getting it implemented into the field in the immediate prelude to world war ii u.s medium tanks are generally built around machine guns lots and lots of machine guns however like other nations such as the uk the question was asked what happens if we come across an enemy tank until then the us army didn't have an anti-tank gun of any sort in service beyond possible use of a 50 caliber which in fairness wasn't actually bad against most tanks of the era still once the 37 millimeter had been adopted as the towed gun it wasn't too much of an issue to mount the 37 millimeter onto a turret to give the tank a better anti-tank capability t5e2 was an experiment to see if the 75 millimeter gun would be better at the anti-infantry role than all the machine guns and this proved to be effectively the prototype concept for the m3 medium tank however the successful invasion of france and the emphasis given to the use of panzers resulted in two decisions the first was the creation of a tank destroyer force this led to the question of what the best weapon would be to destroy enemy armor although the 3-inch gun was available and trialled no vehicle suitable for mounting it was available eventually the tank destroyers were fitted with 37 millimeter guns in the light platoons and 75 millimeter guns in the heavy platoons as the best tank tank-destroying weapons the us army could field simultaneously work was being undertaken to increase the firepower of the medium tank the best gun that could be fielded in a medium tank was again 75 millimeters actually a slightly more modern 75 millimeter than that found on the m3 tank destroyers but similar enough it was a natural progression to move the same 75 millimeter to the m4 when it entered production after the m3 in early 1942. with instructions put out to see whether the three inch gun or the 105 millimeter howitzer could also be installed as an alternative this is why the m4 came with such a large removable gun shield any gun was supposed to be installed into the same turret just simplifying production you just add the module so again the m4 was being built with the best gun that the us had which could be put into the tank it wasn't anything to do with tank destroyer doctrine or artillery doctrine or the capability of high explosive or any of the other claims going around in the meantime experiments to get the three-inch gun onto the battlefield continued it proved difficult as the gun not intended for vehicle mounting proved to be rather large heavy and cumbersome for most vehicles some of these attempts such as t-40 or t-57 are to be found in world of tanks eventually it was decided that with a purpose-built simple turret with no roof and no coaxial machine gun the three-inch gun could be mounted onto the m4 chassis of course this led to the m10 being able to mount the three inch into the m4 as a tank destroyer of course is an entirely different kettle of fish to mounting it as a tank weapon the m10 was an expedient heavier than it needed to be simply because of the need to put dead weight on the back of the turret to balance out the gun on the front a situation which would be exacerbated in the case of a proper turret with frontal armor and a machine gun in a tank which already was approaching the limits authorized for shipping and tactical bridging the attempt to armed three-inch gun into the m4 medium was abandoned salvation was to come in the 76 millimeter gun the three-inch gun was an older design dating back quite a few years the version eventually used by tank destroyers being a sort of a cobbling together with the barrel of the three-inch anti-aircraft gun t9 and the breach and carriage of the 105 millimeter m2 howitzer being something of a hack however it was anything but efficient and in more recent years improvements in metallurgy had resulted in the possibility of a new design started from scratch which in effect gave you the same 3-inch gun for half the weight or a bigger gun for the same weight hence the split here between the 90 millimeter which would replace the three inch on m10s to make m36s or the 76 millimeter designed to fit with a three inch gun could not the choice of the 76 millimeter was a matter of rationalizing production the three inch gun was a known quantity and apparently quite capable of performing the role for which it was intended with production lines already set up for the projectiles it made no sense to spin up yet another ammunition production line for projectiles for the new anti-tank gun nor for the creation of a new set of machine tools for boring tubes in this new caliber it also meant that it could shave off a whole bunch of time normally required for testing as a result the 76 millimeter was placed into an m4 for trials in the summer of 1942 after the boffins at aberdeen had finished putting it together and tested it to make sure it mechanically worked sufficient faith was placed in the tank that it was standardized as a substitute vehicle meaning it could be used instead of the 75 millimeter tanks so that the us forces would have an even better anti-tank capability for the likely invasion in north africa later on in the year armored force were most pleased to hear this development worrying only that the larger gun would still carry a useful load of ammunition and that it would not delay production of tanks overall so they wouldn't be held back from getting into the fight it is worth observing at this point that nothing more troublesome than a panzer iv had appeared on the german side with the l43 7.5 centimeter gun taken to the field only a couple of months prior until then the shermans with their 75s had the match of the german tanks and although the longer german gun had begun to equal the scales it wasn't as if the 75 millimeter was ineffective still if the americans could put a higher velocity cannon into the field that meant that the us could engage accurately from further out the importance of velocity at this point wasn't so much in penetration as much as the accuracy a shorter time of flight means a flatter arc more tolerance for range estimation errors and less need for lead this inherently gives the lie to two claims firstly that the m4 was not supposed to engage enemy tanks after all they've just been given firepower equivalent to the in-service m10 tank destroyers and what would eventually be placed onto the future m18 tank destroyer the only reason for doing so is increased anti-tank capability secondly that the us were not being proactive they absolutely were in giving the tanks more firepower than they currently needed in case they needed more when the next wave of german tank improvements came out of course this plan didn't happen no 76 millimeter tanks part took an operation torch or any operations in north africa at all that's because armored forts were not happy with it you will recall from my various videos that i place great emphasis on ergonomics it's all very well having the great technical capability on the tank but if it cannot be efficiently used what's the point well armored force had a similar philosophy the 76 millimeter conversion into the small m4 turret did indeed technically work indeed such conversions would happen later on in the war in the field and would also be distributed to allied nations after the war when the us was disposing of its own surpluses however there were a slew of faults that for the americans it was decided not worth building being as there was apparently no particular impression of being undergone with the current tanks it was possible to take the time and do it right so armored force told ordnance branch to throw it away and start over something else ordnance had started over with at the same time was the basic tank design in the first place with m4 production in full swing ordnance felt that they could devote some time towards designing an entirely new tank of increased protection and firepower as the m4 in production enter the t20 series of tanks designed from the ground up to carry a 76 millimeter unsurprisingly being designed from the start to take the new gun the turret configuration was far superior enter thus the easy six sherman was due for a midlife update in its design anyway the steeply stoked frontal armor was difficult to make the hull hatches were small the internal volume limited and the tank had a bit of a habit of catching fire more often than desired not any more than any other tank mind but more often than the americans were happy with the ride could also be improved a bit as well all these various problems were addressed in the m4e6 the large hatch sherman had less of a front slope with thicker armored compensate the ammunition was put into wet stowage to reduce the chances of fire a new horizontal valued suspension system was installed and the 76 millimeter turret was lifted off the t23 medium tank and placed onto the m4 it was sent off for trials in june of 1943 and passed handily with only minor tweaks required to include rejecting the suspension system pending redesign by august 1943 the decision had been made all us army m4 medium tank production would switch to the 76 millimeter gun of course it would take time to retool the production lines so the plan drawn up by the manufacturing section of army supply forces envisioned production starting december 1944 with all of the production lines barring a few contracts for rebuilds and the like being changed over by february note this is just us army production 75 millimeter production would still continue for the marines and export orders plus of course eventually non-medium tanks like assault tanks such as the jumbo sherman again it is instructive to note the timeline against what the germans were actually fielding by the time this decision was made the us was well enough familiar with tigers which were being used in small numbers but though ferdinand and panther had just had their combat debut on the russian front no useful information about them had made the way to the us at the time as far as the americans knew the 76 millimeter gun could take care of anything they were likely to meet of course once production starts that's still quite different from fielding tanks produced in early 1944 still had to make their way to ports get shipped over to the uk and then issued to the field units by the time d-day preparation started with some 200 tanks in the uk thank you to commanders who disinclined to hubble themselves by introducing a new tank to add to their training and logistical requirements there seemed to be no need for them this was the us's second mistake and not really anything you can place the blame at to the feet of the design or doctrine guys in the us the first mistake possibly only truly knowable with the benefit of hindsight was not creating the hvac round until after the 76 millimeters limitations were made clear this was not a doctrinal failure it was a failure in intelligence both in the belief in the ability to penetrate the front of the german tanks and the numbers of those tougher tanks that they were liable to meet statisticians will probably be very familiar with the german tank problem it's a fascinating assessment of how to determine just how many tanks the enemy has made by looking at serial numbers of those captured the statistics were actually correct but a little bit too late to help really it took a month for the 76 millimeter tanks to be brought over to france only to discover that the gun was not as capable against thick german frontal armor as had been hoped the british had taken a different route with their own upgrade program those ergonomic issues which us armored force had decided with deal breakers and field in the tank were considered to be just the cost of doing business for getting a hole puncher into the sherman quickly enough to make a difference basically it's the old argument between good enough now and perfect next week in normandy sherman fireflies proved the wisdom of good enough now the korean war would prove the wisdom of perfect next week with operations in late 44 and early 45 kind of splitting the difference in any case the fielding finally of the 76 millimeter tank now gives us the sherman yet again equipped with an equivalent gun to the tank destroyers tds never seem to get hammered for inadequate firepower but the usm4 is do for some reason 75 millimeter m4s did prove to retain their popularity though because of their better high explosive round which was what they tended to fire the most the preference to retain 75 millimeters even when given the option of moving to the 76 millimeter at the time though is more of a an incidental result than any doctrinal choice so there is the story of how the 76 millimeter m4 came to be it was part of the policy of giving the tank the best anti-tank firepower it could have whilst retaining its usability and versatility its delay into service had nothing to do with doctrine mcnair's personal opinions on tank on tank combat or anything else notwithstanding it was the result of deliberate and rational decision making to get a new high-velocity gun into a tank with a minimum of disruption to the production and supply system while simultaneously not landing the cruise with the tank which is more difficult to use than it needed to be hope you found the video interesting and informative and we'll see you on the next one

Channel: The Chieftain

Views: 133,481

Keywords:

Id: 9bQHw_n_gPs

Length: 16min 5sec (965 seconds)

Published: Sat Mar 06 2021