tanks/vehicles The T30's Ammo Box

[Sirchby 3,711]

 

The T30 heavy tank has vague information when it comes to ammunition load. Some claimed it’s only able to fire HE, some said it only has low penetrating AP round, while the others describe it as having high penetrating “M111 AP” &“M112 APCR” that can penetrate 276 mm & 320 mm of armor, respectively.

 

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<< Some Problems >>

While some of them are true, there is so little explanation on how the T30 acquired such loadout or achieve such penetration, leading to “what if” situation where the shells are configured according to whatever related sources publicly available.

 

1. It only fires HE shell

The most common misconception about the T30 is that it only has HE shell. Some people claimed so due to the reason that it’s armed with a massive, but low velocity 155 mm T7 gun used for anti-fortification & destroying building, instead of dedicated anti-tank gun such as the 105 mm T5E1 mounted in T29. Although it’s understandable since many referenced the source from R.P. Hunnicutt’s book; Firepower – A History of the American Heavy Tank.

 

2. It fires low penetrating AP round

Information available from other threads usually points out that the 155 mm “AP” fired from 155 mm T7 was unsatisfactory & only resulted in low anti-tank penetration performance from velocity loss. I will explain this later below.

 

3. "M111 AP" & "M112 APCR" that can penetrate 276 mm & 320 mm of armor

So far, it’s very popular as these rounds are available in World of Tanks, used by both T30 & T95, even goes so far that the T110E3 & T110E4 received much improved version with E1 designation in the back that can penetrate 295 & 375 mm of armor. The projectiles in particular are “M111” AP, & “M112” APCR. It’s interesting & confusing at the same time… The only known use of designation “M111” is a 105 mm APFSDS “Hetz” intended to penetrate the Soviet T-72. While the “M112” is actually an AP round of the 155 mm gun.

 

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<< Opening The Ammo Box >>

As such, I suggest a structured weapon loadout for the T30, since we know that the heavy tank is confirmed (twice) & will be introduced at some point in the future. Let's start from the basic. The 155 mm T7 L/40 is a 155 mm gun of the T30 heavy tank, developed from a shortened 155 mm M1 L/45 "Long Tom", conceived as early as 14 September 1944. It was developed alongside with the T29 heavy tank armed with 105 mm T5E1 L/65 gun.

 

T30 had up to 5 different ammunition available for use. Starting from HE, WP, APBC-HE, APCBC-HE, & APCR. The specification will be listed as fired from the T7.

 

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1. M107 HE

 

A standard high explosive shell used on all American 155 mm gun in WWII. Weighing 95 lb (43.09 kg), with an explosive filler of 15.13 lb (6.86 kg) TNT, this was primarily used as anti-fortification. It was also a default shell of the T30.

 

M107 HE

Projectile mass: 43.09 kg (95 lb)

Muzzle velocity: 717 m/s (2300 ft/s)

Explosive type: TNT

Explosive mass: 6.86 kg (15.56 lb)

Fuze type: P.D. M51A4

 

Specification:

Spoiler

 

2. M110 WP

 

Smoke shell, used to provide smoke screen with 15.6 lb (7.07 kg) of white phosphorous. The ballistics & configuration are similar as the M107 HE.

 

M110 WP

Projectile mass: 44.63 kg (98.4 lb)

Muzzle velocity: 717 m/s (2300 ft/s)

Smoke type: WP

Smoke mass: 7.07 kg (15.6 lb)

Fuze type: P.D. M51A4

 

Specification:

Spoiler

 

3. M112B1 APBC-HE

 

An armor-piercing round. Weighing 100 lb (45.36 kg), with an explosive filler of 1.44 lb (653 g) Explosive D, it was used as an anti-concrete shell, or as an anti-tank in secondary tank destroyer role. The difference between M112 & M112B1 is the cap. Performance-wise, both are identical.

 

This is a V50 penetration table on various AP projectiles tested by American from Canadian AFV Technical Situation Report No. 34, showing some well-known shell in service during WWII, including the 90 mm T33, but let's get to the point.

 

At the most bottom of the table, It's listed that 155 mm T7 gun fired 100 lb AP M112B1 at 2200 ft/s. The penetration table on the right shows how much it can penetrate homogeneous armor plate, at only 170 mm penetration from point blank against vertical armor (same penetration of the 90 mm M82). Compared to 155 mm M1 above it, firing at 2745 ft/s, penetrating much higher at 198 mm. This is because, as aforementioned, the T7 is a cut down M1 gun with shorter gun caliber length.

 

M112B1 APBC-HE

Projectile mass: 45.36 kg (100 lb)

Muzzle velocity: 670 m/s (2200 ft/s)

Explosive type: Exp. D

Explosive mass: 653 g (1.44 lb)

Fuze type: B.D., M60

 

Specification:

Spoiler

 

4. T29E1 APCBC-HE

 

The weapon loadout also specified different armor piercing capped, which is the T29E1. It was an experimental APCBC-HE shell developed for 155 mm gun specifically to deal against heavily armored targets. The T29 was also known as M112 APBC-HE when the penetrating cap was removed with the final weight reduced to 100 lb. The explosive mass is 1.5% (653 gr) of the shell weight (100 lb), same as the M112. The muzzle velocity is probably also similar, but reduced if fired from T7.

 

 

The ballistic limit given is 2533 ft/s against 203 mm at 30° from vertical, measuring the vertical armor, that would mean about 268 mm from point blank range, substantially higher compared to M112B1. However, this is as fired from M1, not T7. The velocity of M112B1 is 545 ft/s less when fired from it, & it also applies for the T29E1. The point blank penetration as fired from T7 would be only roughly 195 mm. It decreases a lot, but it's still higher compared to only 170 mm penetration of the M112B1.

 

 

 

T29E1 APCBC-HE

Projectile mass: 45.36 kg (100 lb)

Muzzle velocity: 670 m/s (2200 ft/s)

Explosive type: Exp. D

Explosive mass: 653 g (1.44 lb)

Fuze type: B.D. T70

 

5. T35E1 HVAP

 

An armor-piercing composite rigid projectile developed for the T30, in response to the Army's dissatisfaction toward the armor-piercing performance of the 155 mm T7. It was modified from M1's T35 HVAP, with structural design similar to 90 mm T30E16/M304 HVAP on the multi-piece carrier construction.

 

The muzzle velocity as fired from T7 was 3100 ft/s (945 m/s), with the projectile weighing 57.2 lb (25.94 kg, about a kilo heavier than IS-2's BR-471 AP).

 

Penetration figure given from OCM 27195 outlines that the T35E1 performance is given at 178mm against 30° armor from 2000 yards, compared with 216 mm of the 105 mm T5E1.

 

If we're looking for its vertical point blank penetration, we must extrapolate the numbers from the T35 first. Weight of the T35 is 56.5 lb (25.62 kg), & muzzle velocity at 3630 ft/s (1106 m/s).

 

Ballistic limit of the T35 HVAP versus rolled homogeneous armor:
0° - 14.00 in (355 mm) - 3365 ft/s (1031 m/s)

 

So, we know the ballistic limit of the T35 at 1031 m/s. Measuring the penetration to point blank range should give around 392 mm of penetration. Now, if we decrease the velocity from 1106 m/s of the T35 to 945 m/s of the T35E1, & add a little bit weight of it, the final result is 316 mm of penetration.

 

155 mm T35E1 HVAP

Projectile mass: 25.94 kg (57.2 lb)

Core diameter: 90.1 mm* (3.55 in)

Core mass: 6.8 kg (15 lb)

Core type: Tungsten Carbide

Muzzle velocity: 945 m/s (3100 ft/s)

Penetration: 316 mm  0° Point Blank

 

*It's unknown how exactly big the core is. But assuming the core diameter-to-weight ratio of 90 mm M304 is used:

Projectile: T30E16 / M304
Weight: 7.62 kg
Core Diameter: 47.7 mm
Core Weight: 3.6 kg
Core Material: Tungsten Carbide
Core Diameter-to-Weight ratio: 13.25

 

If 90 mm core is used for 155 mm T35E1:

Projectile: T35E1
Weight: 25.94 kg
Core Diameter: 90.1 mm
Core Weight: 6.8 kg
Core Material: Tungsten Carbide
Core Diameter-to-Weight ratio: 13.25

 

The core diameter-to-weight ratio of both 90/47 mm & 155/90 mm is same.

 

And there we have it, all the confirmed ammunition the T30 has. Be reminded that the measurement is not 100% accurate as there is no exact penetration table found on the T29E1 & T35E1, so using DeMarre equation is an alternative way to measure the numbers manually.

 

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<< Additional >>

 

A bit of live firing test video of the T30 using "fin missile", which is assumed to be a fin-stabilized APDS.

Spoiler

T30 running a firing test from Aberdeen video documentary, firing an experimental fin-stabilized AP round in 1950s.

Unfortunately, there is no known information about its 155 mm APFSDS. Yet. So it's excluded from the suggestion.

 

Special thanks to:

@arczer25

@Conraire

@Whelmy

 

 

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Sources:

• Development History of the Heavy Tanks, T29 & T30, 1945
• Royal Artillery Liaison Letter to the War Office, 1945
• RAC – AFV Technical Situation Report, 1944 – 1945
• TM 9-1901 – Artillery Ammunition, 1944
• AD800469 – Aerodynamic Data for Spinning Projectile
• AD301343 – An Analytical Study of Data on Armor Penetration by Tank-Fired, Kinetic Energy Projectiles, 1958
• R.P. Hunnicutt: Firepower – A History of the American Heavy Tank, 1988

Edited December 21, 2018 by Sirchby
Reconstruction

[SAUBER_KH7 3,326]

Open for Discussion.

 

Please refrain from using red text in the future as it is reserved for staff to use. But other text colors are fine.

 

Quote

1.1.9. [DO NOT] Use red text font in any respect. This is reserved for staff use to highlight problems or statements.

 

 

[Sirchby 3,711]

 

4 minutes ago, SAUBER_KH7 said:

Open for Discussion.

 

Please refrain from using red text in the future as it is reserved for staff to use. But other text colors are fine.

 

Thanks for the quick response 

 

I'll refrain from using it again next time.

[Whelmy 1,970]

The T7 fired the T35E1, those numbers for the T35 would be from a long tom firing it. so the overall velocity from the T7 would be less as would the performance.

 

 

The chief wrote the following a few years ago.

 

Quote

T58's cannon, T180 used to be T7E2. It's basically the same gun with a few tweaks, and it's a rifle. The statistics between T180 and T7 are identical down to the length in calibers and the weight.

Looking at a document dated January 1952, the only shells 'in service' for T7 were HE M101, and Smoke M104. Initially an AP shell M112 was supposed to be fired from the same gun for the armor piercing role. The same document also initiated development of HEP T152 and HEAT T267 with penetration ratings of 7" and 16" respectively.

About a month later, Army Field Forces wrote back saying "Seriously? You want to fire AP rounds out of this thing? Then you're going to need something with a bit more 'oomph' than propelling charge T14, we recommend developing a new charge"

It seems the Army never went that route, maybe the gun couldn't handle the higher pressure. However, they did have a crack at a HVAP round:

Some time later, there's a further document which states:...

"The terminal ballistic performance of the Shot, HVAP, 155mm T35E1 would be less than either the corresponding HEP or HEAT rounds. Therefore, due to the necessity of having a large tungsten carbide core in the HVAP round, it would be more economical to use the HEP and HEAT as the Armor Piercing type rounds for the 155mm guns."

 

 

Ken Estes wrote this a few years back as well

 

Quote

For the T-58 [155mm T7 on M103 hull]: 1000yds 0 55 60deg. 2000 yds 0 55 60
T152 HEP 2600 fps 75lb 7, 7, 7, 7, 7, 7 inches
T267 HEAT 2800 75 16, 9.2, 8, 16, 9.2, 8
It could also use the M112 AP, perhaps the one used in the M40 SPG: 6" at 30 deg 1000 yds [Hunnicutt]

 

They were firing some sort of experimental APFSDS as well

19 mins 38 seconds.

 

Edited December 4, 2016 by Whelmy

[Dark_Lord__94@psn 1,900]

Give us the T30E1 that fired the heat shell drop it as a 7.0 br and you have a high Tier derp gun. Lol that APHE though. How much explosive did it have and was there any other rounds that had less he? Oh and one last thing what's the armor and what is a hep shell haven't heard of that one. 

Edited December 4, 2016 by *Lightening_Drake

[Sirchby 3,711]

6 hours ago, Whelmy said:

The T7 fired the T35E1, those numbers for the T35 would be from a long tom firing it. so the overall velocity from the T7 would be less as would the performance.

 

 

The chief wrote the following a few years ago.

 

 

 

Ken Estes wrote this a few years back as well

 

 

They were firing some sort of experimental APFSDS as well

19 mins 38 seconds.

 

 

So, the T35A1 was specifically made for 155 mm T7?

Okay

 

1 hour ago, *Lightening_Drake said:

Give us the T30E1 that fired the heat shell drop it as a 7.0 br and you have a high Tier derp gun. Lol that APHE though. How much explosive did it have and was there any other rounds that had less he? Oh and one last thing what's the armor and what is a hep shell haven't heard of that one. 

 

The HE mass of the M112 APBC-HE is as much as over 650 g.

Explosive mass: 653 g (1.44 lbs)

Even then, the Maus' 12.8 cm PzGr 43 still has much more TNT-equivalent warhead inside.

 

There's no other round that had less HE, as far as I recall. Why would you need a shell with smaller HE?

 

What's the armor of what?

 

HEP (High Explosive Plastic) = High Explosive Squash Head.

This shell ignores LoS thickness because all it does is to make a big spall into the enemy armor through direct contact with the armor plate, as long as there's no multiple layers of armor.

[Dark_Lord__94@psn 1,900]

1 hour ago, BravoBigBooms said:

 

So, the T35A1 was specifically made for 155 mm T7?

Okay

 

 

The HE mass of the M112 APBC-HE is as much as over 650 g.

Explosive mass: 653 g (1.44 lbs)

Even then, the Maus' 12.8 cm PzGr 43 still has much more TNT-equivalent warhead inside.

 

There's no other round that had less HE, as far as I recall. Why would you need a shell with smaller HE?

 

What's the armor of what?

 

HEP (High Explosive Plastic) = High Explosive Squash Head.

This shell ignores LoS thickness because all it does is to make a big spall into the enemy armor through direct contact with the armor plate, as long as there's no multiple layers of armor.

Ahhh a hesh shell. Feel stupid now. How much armor is on it I was reading the turret was about 280mm. But nothing on the ufp or lfp and what angle both the plates were at. So it's a one shot and then hide because your reload is going to be forever long. About 2 to 3 shells a minute with the 2 loaders. 

[Sirchby 3,711]

On 12/5/2016 at 9:32 AM, *Lightening_Drake said:

Ahhh a hesh shell. Feel stupid now. How much armor is on it I was reading the turret was about 280mm. But nothing on the ufp or lfp and what angle both the plates were at. So it's a one shot and then hide because your reload is going to be forever long. About 2 to 3 shells a minute with the 2 loaders. 

 

Its armor is completely the same as the T29.

The T30 is just a plan to mount a T29 with a new engine & a 155 mm gun.

 

T30, along with T34, use Continental AV1790-3 (2800 rpm)

 

Nonetheless the T30E1 has assisted loading system that can potentially reduce its loading time.

Edited February 13, 2017 by Sirchby

[Dark_Lord__94@psn 1,900]

22 minutes ago, BravoBigBooms said:

 

Its armor is completely the same as the T29.

The T30 is just a plan to mount a T29 with a new engine & a 155 mm gun.

 

Whereas the T29(E1 we have in the game) uses Allison V-1710-E32 (2800 rpm), the T30 uses Continental AV1790-3 (2800 rpm)

 

Nonetheless the T30E1 has assisted loading system that can potentially reduce its loading time.

Just give us the T30E1. 7 br there we go a decent American heavy. We're supposed to get the T30 and T34 in 2016 but I guess will see. 

Edited December 5, 2016 by *Lightening_Drake

[Sirchby 3,711]

1 hour ago, *Lightening_Drake said:

Just give us the T30E1. 7 br there we go a decent American heavy. We're supposed to get the T30 and T34 in 2016 but I guess will see. 

 

Seems fair that way.

 

But BR placement is out from my topic range.

[Sirchby 3,711]

To be frank, the only obscure material to find right now is the full characteristics of T267 & T152.

 

Would not be able to load the T30 with these T58 rounds if they're partially unknown yet.

[Vulpinaut 44]

>100 lb Sabot 

 

Jesus Christ. Can't wait for that to hit ammo racks and deal zero damage or bounce off of King Tiger UFP.

[Sirchby 3,711]

Sorry, it was an oversight.

 

The correct weight of the T35E1 HVAP is 60 lbs (27.21 kg) with 15 lbs (6.8 kg) core.

Edited December 5, 2016 by BravoBigBooms

[ustinodj 5,952]

Considering that APHE should overmatch a Tiger 2's LFP, give at 6.7, if it does not get 6.7 give the HESH and HEAT.

 

(Also depending on how kind Gaijin is feeling the HE should have ~60mm pen (HE pen on Brumbar), which is enough to pen everything frontally)

[Sirchby 3,711]

1 hour ago, ustinodj said:

Considering that APHE should overmatch a Tiger 2's LFP, give at 6.7, if it does not get 6.7 give the HESH and HEAT.

 

(Also depending on how kind Gaijin is feeling the HE should have ~60mm pen (HE pen on Brumbar), which is enough to pen everything frontally)

 

No, it doesn't overmatch.

 

Even then the sloped penetration output is still insufficient to penetrate King Tiger H from level terrain.

[ustinodj 5,952]

8 hours ago, BravoBigBooms said:

 

No, it doesn't overmatch.

 

Even then the sloped penetration output is still insufficient to penetrate King Tiger H from level terrain.

I thought they changed overmatching so any calibre >130% plate thickness is much easier to pen. 

[Panzerzwerg 2,682]

17 minutes ago, ustinodj said:

I thought they changed overmatching so any calibre >130% plate thickness is much easier to pen. 

 

130% of 150 is 195. 

[ustinodj 5,952]

29 minutes ago, Panzerzwerg said:

 

130% of 150 is 195. 

LFP is 100mm thick no? 

[Ta_Kanata18 1,109]

1 hour ago, ustinodj said:

I thought they changed overmatching so any calibre >130% plate thickness is much easier to pen. 

Is your shell diameter bigger than plate thickness?

>yes: Is your gun have enough pen?

       >yes: overmacth

       >no: non pen

>no: Is your gun have enough pen?

      >yes: there is a chance of ricochet

      > no: non pen

Edited December 6, 2016 by Ta_Kanata18

[Sirchby 3,711]

55 minutes ago, Ta_Kanata18 said:

Is your shell diameter bigger than plate thickness?

>yes: Is your gun have enough pen?

       >yes: overmacth

       >no: non pen

>no: Is your gun have enough pen?

      >yes: there is a chance of ricochet

      > no: non pen

 

Just a reminder that:

 

Overmatch only occurs if the shell has at least over 30% bigger caliber than actual armor thickness.

 

Also, enough pen "of what"?

 

You still need angled penetration numbers to pierce a tank's main frontal armor instead of vertical number even with Overmatch advantage available

 

[Lunafreya 17]

No one gonna buy T29 if gaijin add this tank )) 

[MiseryIndex556@psn 13,155]

51 minutes ago, Lunafreya said:

No one gonna buy T29 if gaijin add this tank )) 

 

This tank will perform way worse than the T29. The APHE has very little pen, at the BR it will likely see. Its reload is twice as long. The armor is exactly the same, as well.

[Sirchby 3,711]

Its APHE is "not so little" though.

About comparable to PzGr 39 KwK 36 & M82 M3 with around 5x HE warhead inside.

[Sirchby 3,711]

The struggle between readying the ammunition suggestion post & waiting inbound Devblog is real.

[_EQUAI_ 356]

2 hours ago, BravoBigBooms said:

The struggle between readying the ammunition suggestion post & waiting inbound Devblog is real.

The suspense is real indeed