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Sherman Tank Myths - The Misery of Having 'Facts' to Work With
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Sherman Tank Myths - The Misery of Having 'Facts' To Work With By Copyright ©2015, J.D. Neal, All Rights Reserved Can anyone blame anyone for not being able to “get the facts right”. I was researching the question of whether or not the 75-mm rounds used in the Sherman tank’s M3 cannon would chamber in the 76-mm M1 series gun. I had only basic numbers to work with (overall length, cartridge case length, etc.) courtesy of TM9 1901 (Artillery Ammunition) dated 29 June 1944. So I started with picture compares. My process was to take a snap-shot from case bottom to projectile tip from the TM9 1901 pdf. Using a scale of x100 pixels per inch I laid them out as close as I could get, knowing I’d never be perfect: the 75mm M61 APC round was 26.29” long and hence 2629 pixels long and the 76mm M62 APC round 35.59” or 3559 pixels. The first pictures I used were misleading. They did not show the bell on the 75-mm case. I later found pictures that clearly showed that the 75-mm case was bottlenecked (if only slightly) while the 76mm was straight-cased. (Narrowing towards the projectile; a line drawn along the side confirmed there was no neck.) That was a letdown. Still, I wondered about the story of Shermans using 75-mm howitzer ammunition on Tarawa. It is also a bottle-necked case like the 75mm gun case with the shoulder further down on the case. So, perhaps the 75mm gun could fire 75mm howitzer rounds, since the worst result was likely a “blown out” case, and perhaps erosion in the throat if too many howitzer rounds were fired. If that was true, would the 75mm case fit the 76mm breech despite the different design? I was curious as to how different the 76mm and 75 cases were and decided to crudely measure them using pictures. I did some test measurements and things did not add up. It took a while to figure out that the US Army’s technical manual was wrong. Or perhaps only misleading. According to the manual: The 76mm M62 APC round is 33.8” long and has a 9.8” long shot. But, the M42 HE round is 33.3” long and has a 12.4” long shot. How could the HE round have a projectile 2.6” inches longer than the APC round but be a half inch shorter? The 76mm M79 AP round (no ballistic cap)
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Sherman Tank Myths - The Misery of Having 'Facts' to Work With facts that are wrong or misleading can cause confusion.
Transcript of Sherman Tank Myths - The Misery of Having 'Facts' to Work With
Sherman Tank Myths - The Misery of Having 'Facts' To Work WithBy Copyright 20!" #$%$ &ea'" ('' )ights )eserve*Can anyone +'ame anyone for not +eing a+'e to ,get the facts right-$ . /as researching the 01estion of /hether or not the 2!-mm ro1n*s 1se* in the Sherman tank3s M4 cannon /o1'*cham+er in the 25-mm M series g1n$ . ha* on'y +asic n1m+ers to /ork /ith 6overa'' 'ength" cartri*ge case 'ength" etc$7 co1rtesy of TM8 80 6(rti''ery (mm1nition7 *ate* 28 #1ne 899$ So . starte* /ith pict1re compares$My process /as to take a snap-shot from case +ottom to pro:ecti'e tip from the TM8 80 p*f$ ;sing a sca'e of C ro1n* is 44$E- 'ong an* has a 8$E- 'ong shot$B1t" the M92 HF ro1n* is 44$4- 'ong an* has a 2$9- 'ong shot$ Ho/ co1'* the HF ro1n* have a pro:ecti'e 2$5- inches 'onger than the (>C ro1n* +1t +e a ha'f inch shorterC The 25mm M28 (> ro1n* 6no +a''istic cap7 is 28$E- 'ong /ith a 8$2- shot$Ho/ co1'* the M28 +eshorter an* yet have the same 'ength of shot as the M52CG(s . 'earne* more . rea'iAe* the pro:ecti'es co1'* have +een inserte* *eeper into the case" hence having a shorter overa'' 'ength$ This /o1'* a'so e ro1n*s *espite +eing ,S1per Charge*-$H. 'ooke* at the 4-inch ro1n*s for the M!" M5" an* M2 g1ns 6there /ere t/o types of 4-inch g1ns in 1se in the 890s an* the T8 chosen for gro1n* force 1se in tanks an* g1n motor carriages /as a *erivative of a 8E /eapon7$ My +rain /as +ogg'e* yet again$ Since the 4-inch g1n 1se* the same pro:ecti'es as the 25mm 61se* them ?rst at that7" .3'' 'ist them o1t in M52 (>C" M28 (>" M92 HF or*er= overa'' 'ength 4!$5-" 4!$9-" an* 49- an* pro:ecti'e 'ength 8$E-" E$8- an* 2$9-$ The M28 is 01ote* /ith a *iBerent 'ength pro:ecti'e than the 25mm M28 6B;T THF %FS.I&F)S ;SF% THF S(MF >)D#FCT.JF" %.%&3T THFKL7$ The 49- 'ong M92 HF ro1n* ha* a 2$9- 'ong she'' /hi'e the JD&IF) M52 an* M28 (> ro1n*s ha* a shorter shot$. 1se* my pict1res an* meas1re* *o/n from the tip of the 4-inch an* 25mm M52 pro:ecti'es an* fo1n* that 'ength of 8$E- 68E0 piC ro1n* for the 2!mm /as meas1re* /ith the +a''istic cap since it is 01ote* as +eing 4$2P 'onger than the cappe* M52 pro:ecti'es$ (n* yet they are the same /eight$. *i* not e ro1n*s 1se* might +e referre* to as either since some *i* have asma'' e
