Because despite this projectile being technically accepted into service during the war, it was inferior in every possible way to the M62 APC shell. I know in the early years of the war they produced some amount of uncapped solid shot as substitute standard ammunition until the production of more complicated capped AP shot was established. But, I believe by the time the US began fielding AFVs armed with high velocity 76mm gun this was no longer a problem.
Anyone’s got info on this?
It’s possible the M10 fired M79 given it was in service earlier than other 76 mm armed vehicles.
I agree, but I would like to see some actual proof.
Is this a troll topic based on the recent APHE rework discussion? 😏
Not at all. ;) I’m just curious if I should even consider this shell when thinking about tank battles on the Western Front. (and Eastern Front I guess, since the US supplied 76mm shemans to the soviets too. The help they are very ashamed of and trying to minimize it’s significance whenever possible :)
There was this chart showing that M79 is pretty much superior at all angles compared to M62.
Only at long ranges the M62 was was better due to the better ballistics.
There’s also the simulation of the M62 and M79 vs. a Jagdpanzer 38(t), which showed how much better M79 was against sloped armor. (Edit: Wrote M62 by mistake)
With the light penetrator and rounded nose, M62 just doesn’t have the best 0-30° penetration to begin with.
I’m still convinced that M62 and M82 were just used due to the fear of German tanks employing FHA that could defeat the AP rounds.
Like, imagine a Panther mantlet being face hardened or a Tigers front. At 500m the 76mm AP would probably fail to penetrate that even at 0°.
Before T33 was developed the US AP had a rather soft nose, in fact it was the same hardness as that of the APC shells. Except in APC the cap protects it, which the plain AP lacked. As a consequence, the performance of US plain AP when fired from high velocity guns against thick armour between approximately 20-45° was lackluster when compared to British AP.
So I’m sceptical about the claim that
M79 is pretty much superior at all angles compared to M62.
Only at close to 0° as well as at high obliquity armour it might outshine the M62, at relatively close ranges.
5" was like the max. pen of M62. Depending on the armor hardness the M79 will still pen that at 1km.
But will it pen the same target at lower ranges down to point blanc? Did you forget about the shatter gap?
A bit of a side note, its interesting to compare the theoretical performance of this other US AP shell with actual test results:
Hmm. Well I have no data for that.
But it’s clear that the round would have a massive advantage in penetrating sloped armor.
It’s also able to pen 4" at 30° at muzzle velocity. If it can do that it can also penetrate 4" from 0 to 1km.
No tank had more than 100mm of flat armor, so it doesn’t really matter. (Maybe Tiger mantlet but M62 isn’t going through that either).
Unfortunately, things don’t work this way IRL.
Despite some “actual real historic sources”^tm showing graphs like this here, that show the penetration curves gently sloping towards some value:
it actuality the terminal ballistics become much more complicated once we need to take shell nose shatter into account. It becomes impossible to capture every nuance of it’s IRL behaviour in a two-dimensional (no pun intended) graph like this.
Here, look:
As you can see, the M79 projectile cannot stay intact at angles over 20-25° for striking velocities high enough to perforate a 4" plate, even against armor this soft (110kpsi = approx 225 BHN)
Yes
Ordnance had developed both AP shot and AP shell rounds for the 3-inch and 90mm guns. US M62 AP shell rounds were capped, and so are identified as APC in the table, while the un-capped M79 solid shot rounds are listed only as AP. Even though the numerical labels may indicate otherwise, the M79 AP shot rounds were in fact the earlier rounds to be issued, and were generally replaced by the M62 APC shell rounds after the Tunisian campaign…
Source: The Chieftain's Hatch: US Guns, German Armour, Pt 1 | History | World of Tanks
So in short, before/during the Tunisian campaign, M10s were more likely to have usd M79.
Afterwards, M62 was more likely.
@KillaKiwi If you are brave enough, I can recommend reading these two books. At least the parts relevant to tank fired projectiles:
Well, that doesn’t change what I said. It will pen 4" of flat armor even at 1km.
Of course the penetration decline against 30° is quite substantial, but that’s like the weakness of most AP rounds.
But it’s like a trade-off. You lose angled armor penetration and to some degree flat armor penetration for being able to pen a Tigers side armor when the impact angle is 25° or more.
Same applies with a Pz IVs front armor.
But if we consider your graph, it will still penetrate in both instances at 500m. So the benefit doesn’t seem substantial.
Thanks. Can you tell, off top the your head, when the M10 TDs were accepted into service? Were they already in use by forces in North Africa at that time?
I’m going to look this up.
iirc they have their combat debut in Tunisia actually.
I would assume that the M62 increases penetration range against the Tiger, due to flat armor from 0-30° and the better ballistics, while the M79 has the advantage that the sides of the Panthers become vulnerable when the front is angled 30°.
Something like that:
As much as I respect Nick, I still would like to corroborate his info by a secondary, independant historical source. Like, what types of ammunition the tankers in Italy and later WEurope carried in their tanks? I wonder if some memoirs can shed light on this.
If anybody got anything like that, feel free to post it in this thread.
