Tankers talk (Long post)

[Jigster]

Fire Ant, muzzle velocity and shell weight are THE single most important part at looking at ballastics and penetration. .5 X mass X velocity = kenetic energy, otherwise known as penetration force at target. This lessens as wind resistence and gravity decelerates the shell. It TOTALLY determines ballstics. i.e., higher the muzzle velocity, the flatter the trajectory, which is why the 75L70 on the Panther was such a great gun.

Once again I will repeat, ALL guns during WWII carried armor piercing cap rounds. Because of this it gives a good medium for gun comparsion. Basiclly it shows the "brute force" of each gun. There were literally millions upon millions of APC rounds used, while HVAP is just a fraction of this.

While APCBC are certainly not high velocity armor piercing rounds( well except the type fired from the 75L70 comparied to US guns...)
it was definately a very effect AP round.

If all the guns carried nothing but HVAP rounds they would fall within the same margins of the APCBC rounds, but not all did so compairing the two seems like a moot point.

During any of the German counter-offensives in the Battle of the Bulge, the American crews were far more interested in getting gas then trying to locate HVAP shells...

- Jig

[Jigster]

 

Originally posted by Paul L:
I think you people need to see the Russian info on the 85mm gun, while the penetration is listed as 90mm @ 30° @ 500 meters.  This is the 80% penetration mark and the 50% ballistic limit value should be ~ 10% higher....or 99mm @ 30° at 500 m

But we're left with a question what hardness are the projectiles tested on I bet there all different.

[URL]http://www.history.enjoy.ru/guns/defin_4.html[URL]

Thanks, thats a great link  

- Jig

[fire_ant]

Originally posted by Jigster:
Fire Ant, muzzle velocity and shell weight are THE single most important part at looking at ballastics and penetration. .5 X mass X velocity = kenetic energy, otherwise known as penetration force at target. This lessens as wind resistence and gravity decelerates the shell. It TOTALLY determines ballstics. i.e., higher the muzzle velocity, the flatter the trajectory, which is why the 75L70 on the Panther was such a great gun.


This is patently incorrect amigo.  If this was the case, then why is the pennetration of the US 76mm superior using ALL ammunition types including your favorite capped ap?

Hardness and density of the shell are factors, obviously.  What the others are I don't pretend to know but the figures speak for themselves.  Did you read the figures?  Go check wargamer.org for yourself if you think I mistranscribed them.

DB

[fire_ant]

 

Originally posted by dosequis:
Well, I've been playing Combat Mission alot, and I need to post these messages to the BBS over there. Because, IMHO, the M4 is overmodelled in CM.

(snip)

CM. Tigers with the AP 88 should be practically invincible at 2000m+ hull down, and again I have seen in CM troops abandon the Tiger I when being fired on by a Firefly at 2500m!!!!!!!!

That is because the Firefly COULD knock out a Tiger at 2500m, probably.  The Firefly is a British adaptation of the Sherman using the fantastic new British AT gun, the "17 pounder" which was a ultra high velocity 75mm gun very similar in performance to the gun on the Panther.  The reason this wasn't mentioned in any of the anecdotes above is because those were interviews of US troops, and the Firefly was only used by the British.

The real question here is why didn't the US mass produce the M4 with the 17 pounder in it?  It would have gone a long way toward addressing the problems the US troops were complaining about, an M4A3E8 with a 17 pounder would have been a formidable weapon.  Why didn't they ever do this, even after the war?  I dont have my books in front of me but I'm pretty sure the 17 pounder had better AP performance than the 90mm gun.  It seems criminal that the US refused to use it.  Misplaced patriotism perhaps?

DB

[Paul L]

 

Originally posted by Jigster:

Thanks, thats a great link  

- Jig

It gets worse cause while Russian standards use the 75% mark and the Brits and Germans use 50% , the Americans use 20% mark . So the 76mm APC round goes from 109 down to 99mm while the Russian 85mm APC goes from 90-99 @ 30° impact.So they look the same to me, anyone know what the plate hardness of the tests are?

[ajbab]

 

Originally posted by fire_ant:
That is because the Firefly COULD knock out a Tiger at 2500m, probably.  The Firefly is a British adaptation of the Sherman using the fantastic new British AT gun, the "17 pounder" which was a ultra high velocity 75mm gun very similar in performance to the gun on the Panther.  The reason this wasn't mentioned in any of the anecdotes above is because those were interviews of US troops, and the Firefly was only used by the British.

The real question here is why didn't the US mass produce the M4 with the 17 pounder in it?  It would have gone a long way toward addressing the problems the US troops were complaining about, an M4A3E8 with a 17 pounder would have been a formidable weapon.  Why didn't they ever do this, even after the war?  I dont have my books in front of me but I'm pretty sure the 17 pounder had better AP performance than the 90mm gun.  It seems criminal that the US refused to use it.  Misplaced patriotism perhaps?

DB

Dont you mean 250m, surely not 2500m against a Tiger. I have spoken to actual soldiers who watched a 17 pounder bounce off a abandoned Panther tank in Italy -repeatedly. and they were much much closer than 2500m. Also all these specifications here are quite nice, but has anyone talked to the soldiers, theres still some left, Posts in US, Legions in Canada and so on. American Vets are not at all like the movies, they are quite truthfull. They will tell you of watching four or five ricochetts going off a Tiger tank and then see the gun turn towards them, then begin to wonder if they will be able to bale out or cook. Not mabey so heroic, but honest.

[Pyro]

I don't think the M4 is a bad tank and I think it will be a useful tank in AH.  It has thicker armor on top than the Panzer IVH and better AA defense.  The next tank we do will most likely be the Easy 8 followed by a T-34/76, but I don't know when that will be as we'll have to put more work into the vehicle model before we can do more tanks.

If I get an urge to go make another long post, I'll post some interesting stuff on the M4 and M26 controversy and the people behind it.  Basically, a lot of it comes down to inflexibility of certain key personnel and offices towards our combat doctrine and needs.

RAM, these are just quotes of different people's beliefs and opinions.  Don't take one and assume it is applicable to all or that it is even correct.  All other soldiers who commented on the reason the German 75mm had a much higher velocity than the American 75mm attributed it to the obvious matter that the German round had a much larger propelling charge.  The U.S. 75mm had a pretty dinky case, whereas the German one is a much larger and necked casing.  It's like comparing a .30 carbine round to a .30-06 round.  There were plenty of other observations on problems with American powder, particularly the amount of smoke it generated.  

BTW, I did notice you didn't even get a nibble on your troll.  You've got to learn to hide the hook better.  



------------------
Doug "Pyro" Balmos
HiTech Creations

[Pyro]

Here's one other interesting quote not relating to tanks.  It reminds me of some of the debates going on when the DoD was looking to replace the 1911.

"The American automatic pistol, caliber .45, will not always pierce for instance, a steel helmet, but the German P38 will fire in one side and out the other side of the steel helmet.  But the caliber .45 slug will cause greater damage to a person's body, while the P38 slug will pierce and makes a small clean hole."

-Sgt Russell Aynes



------------------
Doug "Pyro" Balmos
HiTech Creations

[Paul L]

 

Originally posted by ajbab:

 

Originally posted by fire_ant:
That is because the Firefly COULD knock out a Tiger at 2500m, probably.  The Firefly is a British adaptation of the Sherman using the fantastic new British AT gun, the "17 pounder" which was a ultra high velocity 75mm gun very similar in performance to the gun on the Panther.  The reason this wasn't mentioned in any of the anecdotes above is because those were interviews of US troops, and the Firefly was only used by the British.

The real question here is why didn't the US mass produce the M4 with the 17 pounder in it?  It would have gone a long way toward addressing the problems the US troops were complaining about, an M4A3E8 with a 17 pounder would have been a formidable weapon.  Why didn't they ever do this, even after the war?  I dont have my books in front of me but I'm pretty sure the 17 pounder had better AP performance than the 90mm gun.  It seems criminal that the US refused to use it.  Misplaced patriotism perhaps?

DB

Dont you mean 250m, surely not 2500m against a Tiger. I have spoken to actual soldiers who watched a 17 pounder bounce off a abandoned Panther tank in Italy -repeatedly. and they were much much closer than 2500m. Also all these specifications here are quite nice, but has anyone talked to the soldiers, theres still some left, Posts in US, Legions in Canada and so on. American Vets are not at all like the movies, they are quite truthfull. They will tell you of watching four or five ricochetts going off a Tiger tank and then see the gun turn towards them, then begin to wonder if they will be able to bale out or cook. Not mabey so heroic, but honest.

[/B]

He must be refering to the APDS round and yes in theory it should penetrate the Tiger at 2500m at least thats what Jentz reports.

[Jigster]

 

Originally posted by fire_ant:
That is because the Firefly COULD knock out a Tiger at 2500m, probably.  The Firefly is a British adaptation of the Sherman using the fantastic new British AT gun, the "17 pounder" which was a ultra high velocity 75mm gun very similar in performance to the gun on the Panther.  The reason this wasn't mentioned in any of the anecdotes above is because those were interviews of US troops, and the Firefly was only used by the British.

The real question here is why didn't the US mass produce the M4 with the 17 pounder in it?  It would have gone a long way toward addressing the problems the US troops were complaining about, an M4A3E8 with a 17 pounder would have been a formidable weapon.  Why didn't they ever do this, even after the war?  I dont have my books in front of me but I'm pretty sure the 17 pounder had better AP performance than the 90mm gun.  It seems criminal that the US refused to use it.  Misplaced patriotism perhaps?

DB

First, the 17 pdr is a 77mm. Two, it is not quite as effect at range then the 75L70.
Third, the 77mm was a one trick pony.
While the 90mm is compairable to alot of the bigger AT guns, it's HE capacity, like the German 88 guns, made it better all around weapon.

Both the 75L70 and the 17pdr were not the best HE guns around, which is fine when there is nothing but tanks. But when surrounded by infantry, AT bunkers, or whatever else having a gun with good HE capability can mean the difference between living and dying.

This is also why the Sherman M4A3's 75mm gun was felt effective enough to keep in service, because it was a very good close support infantry gun and the inflexible officers in charge figured that as long as it was capable of at least firing AP rounds it should stay in production. The 76mm was also very good as close support and the US Army seemingly always strived for a very good multi-purpose gun.

17pdr guns took a very long time make it into front line tanks, for the regular 17pdr artillary carrige AT gun had been around some time before it was adapted to the Comets, Challengers, and the Centurions when they were finally shipped.

Besides why would the US need to put the 17pdr on the M4's if the 76mm was sooo good.  

- Jig

[fire_ant]

 

Originally posted by Jigster:
First, the 17 pdr is a 77mm.


You got me, I admit it you are right.


Third, the 77mm was a one trick pony.
(snip)
Both the 75L70 and the 17pdr were not the best HE guns around, which is fine when


Well, ok that is true though these hyper velocity guns arent exactly innefective in HE, just not as good.  But I'll grant you this point for the sake of argument.

   However, even if you grant this argument, they could still have put in a specialised tank killing sherman in each platoon (which is exactly how the Brits used the firefly) and it is still criminally negligent for the US to fail to have mounted the 17pdr on M10 tank destroyers, which the British did to excellent effect.  After all according to the same US doctrine TD's arent even supposed to engage infantry or bunkers or other soft targets.

   Personally I think the reason for this was a mixture of misplaced patriotism and proffit motive, it was important not to interfere with production or proffits nor was it fun to pay british companies for rights to their technology when 2nd rate US technology worked almost as good, and besides even if it took 5 US shermans to knock out one German tank, we had gotten into the war late and still had plenty of people to kill off, (unlike the brits who were running low)  At least they did finally break down and buy the license for the Merlin to put in the P51.

It's a real shame for US servicement that they werent a bit more pragmatic though.  As much as I like the P40, imagine how much shorter the pacicifc war might have been if we had been willing to buy the license for Spitfire Mk V's to use for airfield CAP in places like Guadalcanal, for example (I know they wouldnt' have been good for offensive opps requiring long range, but you couldnt ask for a better airfield defender when it really counted...)

   Also, incidentally it may be worth noting that current US docrtine calls for not using HE rounds in the main gun of tanks to attack infantry, they are only to be engaged with machine guns.  Sounds to me like they have forgotten the lessons of past wars.


Besides why would the US need to put the 17pdr on the M4's if the 76mm was sooo good.  
- Jig

Lol!  I must have got your goat in that other thread!  For the record, I don't think the US 76mm was sooo good, I just happened to be aware that it was a bit better as an AP weapon than the 85mm of the T-34/85.  On the other hand per your argument above the 85mm was a much better anti infantry, anti soft target gun though, and more useful all around, which proved very helpful in Korea among other places...

DB

[Pongo]

The 17 pdr was 76.2mm.
The 77 mm was a toned down 17 pdr used on the comet. It was really 76.2mm as well but was renamed to avoid ammo confusion.

Guys find that Faint Praise book I noted somewhere here. It was doctrine. The Americans could and did make great Anti Tanks guns. There was no profit or technical hurdle involved. The US army war fighting doctrin called for tanks to Blitz throught the holes in the enemy line and exploit. The M4a3(75) was perfect for that role. Tank destroyers were supposed to fight the enemy tanks. Some  probelms. No one told the Germans and Italy led the Allies to believe that German tanks would not be that common. The commanders in the field Pre DDay were offered more 76mm shermans and they turned it down for logistics reasons.

The british had some real issues with building tanks with turrent rings large enough for guns like the 17pdr.
The American problem was mostly doctrine. The Tanks Destroyers were a real force in the army and effective gun tanks would make that command disapear(Which is what happend).
The people that developed guns (ordinance board) tried to stick to the doctrine long after it had been proven failed.

Modern tanks probably disuade the use of MA rounds on infantry for two reasons.
Ammo count on the 120s is down in the low 40s.
They have had problems developing good HE rounds for smoothbore guns. The best seems to be HESH rounds that are not as effective as pure frag rounds against infantry.  

[Jigster]

 

Originally posted by fire_ant:
Lol!  I must have got your goat in that other thread!  For the record, I don't think the US 76mm was sooo good, I just happened to be aware that it was a bit better as an AP weapon than the 85mm of the T-34/85.  On the other hand per your argument above the 85mm was a much better anti infantry, anti soft target gun though, and more useful all around, which proved very helpful in Korea among other places...

DB

I'd just like to point out something in the hyper velocity armor piercing vs armor piercing capped with ballistic cap debate... or HVAP vs APCBC as we call it  

While we have been screwing around with penetration, we never got into effectivness once penetration was achieved. In this the APCBC is somewhat better then HVAP round because of the explosive within the round. Thus I believe for this reason it was far more common round then the HVAP type. Frontal shots, much like shooting a plane with a strictily AP, with HVAP had to hit something vital or shoot through and through (which happened alot some rounds) a tank in order to create catastrophic damage like the  APCBC type did(internal explosion).

I've been going through my books looking into on why so few APCR (Or HVAP to the US) and so far it seems that that the APC and APCBC of the British, US, and German guns was actually better at killing tanks because of this internal explosions. (Okay so I'm repeating myself) It was NOT better at penetrating however and the round was rather usless if it never got inside. The APC and APCBC rounds also were a more flexible round in combat, the like of which were very good at penetrating concrete structures and killing or destroying whatever is inside. The APCS was not used in this role because it would do no damage past penetration.

But anyway like I said before every tank carried them  

I also compairing numbers with the war gamer page and their research and it parallels my stugg, the US 76mm sliightly better at range then the Soviet 85mm at 30 degrees. I guess this is due to bad ballistic characteristics on the round, I'll dig on this. But from what I've seen your right, I just wish I would of found this before responding. I just don't like going with the data off a gamer web page without confirming it myself first   Only point I'd like to make here is that data on the 85mm sometimes does not match one source to another by a large margin, but it matchs mine in this case.

Was checking on the 90mm/17pdr thing too, seems until 2000 yards in HVAP the 90mm is slightly better. This is probably because of the 17 pdr APDS round being so light in comparsion to the 90mm, where up close the weight will help, but at range the flatter shooting 17pdr will still have speed when the 90mm is dropping. In APCBC rounds the 17pdr is better at penetration. I would think the 90mm is a sligtly better APCBC after penetration because of it's size( more explosive).

And ayup the 17 pdr is a 76.2mm, just always called it a 77mm for some reason, guess because it's often quoted as being a 77mm. My mistake. Not the first time  

- Jig

I'll make it a point to not rattle off again with confirming things  

[Pyro]

 

Originally posted by Pongo:
Guys find that Faint Praise book I noted somewhere here. It was doctrine. The Americans could and did make great Anti Tanks guns. There was no profit or technical hurdle involved. The US army war fighting doctrin called for tanks to Blitz throught the holes in the enemy line and exploit. The M4a3(75) was perfect for that role. Tank destroyers were supposed to fight the enemy tanks. Some  probelms. No one told the Germans and Italy led the Allies to believe that German tanks would not be that common. The commanders in the field Pre DDay were offered more 76mm shermans and they turned it down for logistics reasons.

I'll have to put book on my reading list.  I've also been wanting to read Death Traps as well.  The thing about doctrine is rather ironic and you see it mentioned a lot in the quotes I posted.  At the core, U.S. and German tank doctrine were basically the same.  However, they differed in that the Germans weren't so fickle about what they wanted their tanks to engage or not engage.  They wanted them to be able to smash through whatever stood in the way to achieve their objective.

The case of the 76mm is pretty screwy too.  The need for a higher velocity weapon was shown in North Africa and the Ordnance Dept. went to work on the 76mm as a quick solution on 20 August 1942.  By 10 September they had it standarardized and successfully fired from a pilot tank.  But then the project ran into red tape and pretty much sat dormant for over a year.



------------------
Doug "Pyro" Balmos
HiTech Creations

[fire_ant]

 

Originally posted by Jigster:

While we have been screwing around with penetration, we never got into effectivness once penetration was achieved. In this the APCBC is somewhat better then HVAP round because of the explosive within the round.

This is an interesting point, most tank games I've ever played such as ASL (board game) and Steel Panthers etc., seemed to always assume that a penetration always equalled a "brew up" esentially.  Close combat seems to offer more potential results at least.  But especially in the case where say, a Stuart manages to clip the side of a panther in an ambush and penetrate the side armor, just, one imagines that that relatively tiny little 37mm shell might not actually be enough to kill the whole crew or disable the whole tank unless it hit fuel or ammo....

For that matter I know in modern tanks such as the M1 ammo is stored carefully so that it isn't so vulenrable, in a special armored container where theoreticaly at least, even if it brewed up the tank wouldn't get knocked out.  I know the early Shermans were particularly bad about ammo storage, ther was actually a hollowed out part of the armor on the front turret where ammo was stored, later versions kept the ammo in water (I think)... I wonder if anyone knows if German or Russian tanks took cany better precautions than this regarding damage.

For that matter I remember reading one of the anecdotes in Pyros' report where a US tank crewman said someones overcoat hanging in a certain spot saved the crew from being killed by a (I think it was) heat round.  It seems to imply some kind of internal shielding of some sort might be able to help save the crew...

DB