Pershing vs Panther, 90mm T33 APBC

[rexford]

90mm T33 APBC as fired by Pershing may be the second most penetrating steel round of WW II, next to 128mm and ahead of 88L71 APCBC, 122mm APBC and 100mm APBC.

Hunnicutt states in PERSHING that 90mm T33 APBC was reheat treated M77 AP with ballistic cap added, and somewhere it lists a 1000m penetration range against Panther glacis.

If U.S. 75mm solid shot AP penetrates 114mm at 2030 fps, DeMarre estimate for 90mm T33 would penetrate 220mm at 0m with same nose hardness (54.5 Rockwell C).

With reheating of T33 to obtain German nose hardness level (61 Rockwell C), 90mm T33 APBC could penetrate 260mm at 0m and 220mm at 1000m, giving round more penetration at all ranges than 88L71 APCBC.

That 220mm penetration estimate at 1000m is interesting because it equals the resistance of a 0.85 quality Panther glacis to 90mm APBC hits, which suggests that 90mm T33 could penetrate 220mm at 1000m.

Why would 90mm T33 APBC outpenetrate 88L71 at 1000m despite lower muzzle velocity, 2800 fps vs 3280 fps?

T33 is solid shot and does not have armor piercing cap, both of which are advantages over 88L71 APCBC-HE. The HE cavity in ammo weakens the projectile and decreases the penetration by at least 10% to 12%, and armor piercing caps decrease homogeneous penetration by 12% or more, so 88L71 at 3280 fps penetrates about 235mm at 0m (T33 does 260mm).

Based on 1000m penetration range and penetration estimates with increased nose hardness, U.S. 90mm T33 appears to be one of the premier Panther killing rounds of WW II, maybe even better than 90mm HVAP.

90mm HVAP was listed as having less than a 500m penetration range against Panther glacis. HVAP slope effect at 55° is 3.45, giving unflawed Panther glacis a resistance of 293mm at 0°.

90 HVAP penetrates 293mm at 280m, which means the Panther which was penetrated by 90 HVAP at 450m had 0.96 quality (that variable Panther glacis armor quality pops up again).

[rexford]

If T33 APBC has 220mm penetration at 1000m, it also goes through Tiger II turret front well beyond that range.

The main problem with the penetration estimates is that sources list 90mm T33 penetration at 1000 yards as 117mm vs 30° armor, which is the same as 153mm at 0°, well below 220mm.

With less than 153mm penetration at 1000m, T33 would never be expected to pemnetrate Panther glacis.

[Jarmo]

Umm.. which one does CM give Pershings, T33 or HVAP? Whatabout tungsten?

Were all commonly availlable?

[Vanir Ausf B]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Jarmo:

Umm.. which one does CM give Pershings, T33 or HVAP? Whatabout tungsten?

Were all commonly availlable?<HR></BLOCKQUOTE>

CM gives Pershing T33 155mm penetration at 1000m, 124mm vs 30 degree armor at 1000m and 60mm at 60 degrees.

HVAP = tungsten.

CM HVAP penetration at 1000m:

252mm at 0 degree

187mm at 30 degrees

53mm at 60 degrees

[ 07-03-2001: Message edited by: Vanir Ausf B ]

[Ari Maenpaa]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Jarmo:

Were all commonly availlable?<HR></BLOCKQUOTE>

http://www.wargamer.org/GvA/weapons/usa_guns7.html quotes Hunnicut and states that: "There were only limited quantities of APBC and APCR projectiles available for Pershings in Europe."

Ari

[Jarmo]

Gargle.. all these abbreviations make me dizzy...

Did I get the following right?

CM says 90mm AP penetrates 155mm at 1000 meters.

Rexford says it should penetrate 220mm?

Quite a difference.

[Vanir Ausf B]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Jarmo:

Quite a difference.<HR></BLOCKQUOTE>

Yes, I'm sure Tero will be outraged at this blatant bias on BTS's part

[ 07-03-2001: Message edited by: Vanir Ausf B ]

[TT]

Robert Livingstone on the Tanker's Net stated that only very few T33 and APCR rounds were available, more or less on an experimental basis, to the Pershings during the last months of the war.

In one of the two "Pershing vs Tiger 1" incidents, a Pershing engaged a Tiger 1 at 900 yards. The first round, an APCR, hit the final drive and immobilised the Tiger. The next round, a T33 went throught the gun mantlet (it is not clear if this was an early or late-production Tiger, there were quite few of the former in action during the last, desperate months), effectively knocking out the Tiger. The Pershing then knocks out two PzIVs at 1200 yards.

I have not seen either APCR or T33 mentioned in connection with the M-36. Was these rounds only limited to the Pershing?

One last thing: If the T33 was able to penetrate the turret front of the Tiger 2 at long range, why then the hurry to develop the "Super-Pershing"?

[Vanir Ausf B]

<BLOCKQUOTE>quote:</font><HR>Originally posted by TT:

One last thing: If the T33 was able to penetrate the turret front of the Tiger 2 at long range, why then the hurry to develop the "Super-Pershing"?<HR></BLOCKQUOTE>

I think the Super Pershing was a shop modified conversion, only 2 created and never put into production. IIRC they were meant for anticipated city fighting, not really to counter Tiger IIs specifically.

[TT]

According to "Tiger Tanks" by Michael Green the "Super-Pershing" had one, single purpose: To equal the Kingtiger, especially in gun power. As it was, the "Super-Pershing" never met a Kingtiger, neither did the standard Pershing.

AFAIK, the "standard" Persings knocked out one Tiger 1, one Panther and a few PzIVs. One Pershing was knocked out by a Tiger 1 (later repaired) and one was knocked out by a Nashorn. There were probably more incidents, but I haven't been able to find more.

[PzKpfw 1]

Their isa a video Jim Warford told us of on Tanker's ages ago. Of an Jackson doing a live fire test on a Panther, at Aberdeen, one shot in the film was from about 100ms vs the glacis & failed to penetrate.

Regards, John Waters

[PzKpfw 1]

The T-33 round was the first real success the US had in trying to obtain the German APCBC nose hardness IIRC. The US had been attempting to obtain German nose hardness levels since 1st examinations of German Pzgr.39 APCBC.

the problem is the Tiger II was never penetrated frontaly in combat, at least no evidence has been found to date of any.

Good question was the the T-33 round issued to Jackson crews & if so why no mention of its 'effectiveness' vs German Hvy tanks.

The other problem if T-33 went only to Pershing's is their were no engagements between these tanks during the war (Pershing vs Tiger II).

It's also interesting to note how worried US armor was about the possibility of IS-3's entering combat in Korea. If the T-33 could penetrate the Tiger II turret front then it would have no trouble with an IS-3.

Regards, Johhn Waters

[ 07-03-2001: Message edited by: PzKpfw 1 ]

[rexford]

IS-3 turret front was 220mm minimum, and mantlet was 205mm. Problem with IS-3 was glacis, and hitting the small mantlet area on a rounded spherical turret.

Tiger II turret front is 189mm, IS-3 is not only thicker and spherical but is a smaller turret.

U.S. published data for 90mm T33 APBC seems questionable, it would have to have LOWER nose hardness than normal American ammo to penetrate 117mm at 30° at 1000m. It had higher hardness, so something seems wrong.

[kipanderson]

Rexford, hi,

Sorry for asking this here, I tried to use the search engine but it is hopeless.

How can I get hold of a copy of your book? I live in the UK.

I must have missed the announcement.

All the best,

Kip.

[TT]

Not quite sure here, but if I remember correctly from a drawing of the IS-3 the lower half of the turret had a tickness of 220 mm, but the upper part was thinner.

If the T33 was as good as suggested it would still give the Pershing a good chanse against the IS-3. The 90 mm had a much higher ROF and was much more accurate than the Russian 122 mm. So in a shootout the IS would be hit over and over again with heavy shells, something which in the end is bound to do some damage. However, if the T33 wasn't as good as suggested, the Pershing crews had good reason to worry.

As for 88 mm L/71 penetration: It could penetrate 202 mm at 30 degrees angle at 100 m. According to Jentz the multiplier at 0 degrees is 1,2 which give it a penetration of 242 mm. If we then add about 10 percent due to the quality of the German test plate (which was said to be very high) we end up at roughly 267 mm. At 1000 m this adds up to 218 mm.

[TT]

Another one :cool: : The penetration values for the 90 mm gun firing the standard APC M82 seems rather high. It is rated at 120 mm at 452 m, while the Tiger 1 gun, the 88 mm L/56 has just 110 mm at 500 m. In reality the 88 mm L/56 would outperform the 90 mm due to its higher quality ammo. So could it be that the penetration values for the APC M82 are too high, while the values for T33 is more or less correct, but that this round for some reason was very good against sloped armor?

[Matthew_Ridgeway]

Of interest is the M48 Patton Tank was still employing the T33 APBC-T round well into the 1960’s. The round was standardized as M318 AP-T by this time. But it is the same mono-bloc penetrator design with a ballistic cap as shown in Hunnicutt’s “Pershing”. The ballistic reticule for the 90mm M41 gunner’s primary sight was calibrated on right side of scope for M318 (T33). The M36 90mm gun employed on the M47 Patton tank had almost the same reticule layout, with M318 clearly designated on the right side of scope picture. Settings were provided on the ballistic computer for M318 super-elevation. M318/T33 had a relatively long service life.