M Hofbauer Posted June 15, 2002 Share Posted June 15, 2002 the M3 75mm (L40) gun on the Sherman is quite a different gun than the Chaffee's M6 75mm gun. apart from the caliber they are radically different designs. most probably know the story about how a regular 75mm gun wouldn't fit into the Chaffee, so the 75mm gun for the Chaffee was taken from the lightweight 75mm gun developed for the use as aircraft armament for the B-25. The latter, though being a 75mm gun, was considerably weaker (sloer muzzle velocity) than any regular 75mm tank gun. I was fumbling around with tidbits of info on the M6 Chaffee gun (for example I still didn't figure out it's caliber length (Lxx)), when I noticed that in CMBO the Sherman 75mm gun and the Chaffee 75mm have the exact same performance down to the last mm of armor performance on every distance. Is this coincidence, a mistake, or is there a relation bewteen these two guns that I had thought to be impossible (i.e., were they, after all, similar in performance after all)? sorry if that has been covered before, my skull-internal search fgunction did not recall any post on this matter in all the years. Link to comment Share on other sites More sharing options...
Michael Emrys Posted June 15, 2002 Share Posted June 15, 2002 Oh dear, here I go sticking my neck out where probably I shouldn't. But what I recall about the Chaffee's gun that most distinguished it and made its carriage on the M24 possible was a different arrangement for the recoil and recuperation mechanisms. You're right about its muzzle velocity being lower, but I'm not sure that it was all that much lower. I suspect that while the stats on it in CM:BO may be in error, they might not be all that much off. Okay, grogs, show me where I'm wrong! Michael [ June 15, 2002, 05:16 PM: Message edited by: Michael emrys ] Link to comment Share on other sites More sharing options...
von Lucke Posted June 16, 2002 Share Posted June 16, 2002 According to the "Encyclopedia of Tanks" by Crow and Icks, both the M3 and M6 guns have the same MV: 2030fps. The M6 gun also used the exact same ammo rounds as the M3, so one would infer that penetration characteristics where similar, if not identical. Pretty much seems like the M3 and M6 guns are a case of parallel engineering: Two almost identical devices arrived at by different paths. PS: The caliber length of the M6 is 39. Link to comment Share on other sites More sharing options...
lcm1947 Posted June 16, 2002 Share Posted June 16, 2002 I can see why they would have to come up with a different barrel (gun) when putting it on the Chaffee and all but what makes you think they didn't use the same exact 75mm round? I mean here we are at war why would they go to the trouble of designing and manufactureing a new round, unless they were unhappy with the current round of course. I would think that all figures would be the same if the same round was used since the only thing that would effect the performance of the round would be barrel length. Right? Now if the round it's self was truely changed then all performances would be different. But again all depends on how and what the differences were as to how much different the performances would be. I hope somebody like JasonC or some other knowledgeable person jumbs in here. Good question however and I am looking forward to see what is said. Link to comment Share on other sites More sharing options...
M Hofbauer Posted June 17, 2002 Author Share Posted June 17, 2002 Thanks everyone for their contribution. I am going for your explanation that the two guns have similar / identical performance, although an in-depth enlightenment about just how these two very different designs arrived at that would still be interesting. Again, thanks! Link to comment Share on other sites More sharing options...
Gordon Posted June 17, 2002 Share Posted June 17, 2002 See the following link to an article on the Chaffee at AFV Interiors that discribes the M6 75mm gun. Originally designed for the B-25 Mitchell bomber it had a concentric recoil mechanism, thinner/lighter barrel walls than the M3 gun, but fired the same ammo. It does appear, at least according to AFV Interiors that the AP capabilities of the gun might be overstated. Gordon Link to comment Share on other sites More sharing options...
von Lucke Posted June 18, 2002 Share Posted June 18, 2002 From the AFV Interiors article: "The M61 APC could only penetrate 2.4in (60mm) of armor at 1000yds and 2.0in (50mm) at 2000yds, the armor being set vertical and perpendicular to the gun." From CMBO, stats for both M3 and M6 75mm guns: AP penetration at 1000yds / 30deg is 63mm. AP penetration at 2000yds / 30deg is 50mm. The MV of both guns is rated as 619m/s, which equates (=/-) to 2030f/s. So then, who's declination to believe? I tend more toward BTS's favor, but where's Rexford when you need him? Link to comment Share on other sites More sharing options...
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