Steve (BTS): ROF of ISU-152

[Skipper]

I think you stated that ISU-152 had rate of fire something like 1 shot in 1.5 minute. I have a contradicting informtion,. Namely:

Voznyuk, Shapov "Bronetankovaya tehnika", 1987; quoted from http://armor.kiev.ua/Tanks/index.html (in Russian)

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Heavy SPG ISU-152 (1944)

Heavy self-propelleg gun ISU-152 (photo 79) differs from SU-152 only in the chassis, which was from hevy tank IS-2.

Combat compartment of this machine had a 152 mm gun-howitzer ML-20. Ammo load, consisting of 20 separated rounds, included HE rounds of 43.5 kg and AP rounds of 49 kg weight.

Rate of fire was 2...3 shots per minute.

Except the 152 mm gun-howitzer, this SPG, as well as its predecessors, had a 12.7 mm AAMG.

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So, are you sure?

[ 06-03-2001: Message edited by: Skipper ]

[Skipper]

[Commissar]

Whatever the ROF, god forbid you get hit by that thing. It's one thing to be knocked out. It's another to be simply obliterated

[offtaskagain]

Anybody have an armor penetration table for this beast? Is that last picture an 152 or a 122? The barrel looks a little long for a 152

.

[ 06-03-2001: Message edited by: panzerwerfer42 ]

[Username]

I wonder if gun hits on these vehicles should be a more common event. The 152 barrel is just a huge target.

BTW whats that tube attached to the side of the vehicle? Not the extra fuel tank in the back but the one next to the fighting compartment?

Lewis

[Amedeo]

Speaking about the ROF for 122mm and 152mm armed Soviet AFVs, one should also consider that the D-25T gun mounted on ISU-122S SPGs and on late production IS-2 tanks was equipped with a drop breech that surely increased its ROF at least to 3rpm.

Anyway, for the ML-20 152mm gun armed SU-152

also the following sources give 2rpm as normal ROF.

http://history.vif2.ru/su152.html

http://www.crosswinds.net/~armoured/su-152.htm

Regards,

Amedeo

[offtaskagain]

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

I wonder if gun hits on these vehicles should be a more common event. The 152 barrel is just a huge target.

BTW whats that tube attached to the side of the vehicle? Not the extra fuel tank in the back but the one next to the fighting compartment?

Lewis<HR></BLOCKQUOTE>

My guess is a gun cleaning rod, similar to the one carried by Panthers.

[Skipper]

The lower photo is ISU-122 in Lodz, Poland, 1945.

ROF of ISU-122S with well trained crew achieved 5 shots per minute.

[Måkjager]

If you look closely you will see that the "tube" is infact an unditching beam/log

Regards

Måkjager

[Amedeo]

And consider that the ROF of the ISU-122 SPGs should be higher than the corresponding IS-2 tanks because there were two loaders in the ISU (IIRC), don't know about the 'friendliness' of the ammo layout.

So a tentative table could be:

ISU-122S 5rpm

IS-2 w/drop breech 4rpm

ISU-122 4rpm

IS-2 w/screw breech 3rpm

SU/ISU-152 2rpm

Comments?

Amedeo

[Grunto IV]

ZVERDOY!

Andy

[Skipper]

Zveroboy. But that's nickname of SU-122, iirc. This beastie:

[ 06-03-2001: Message edited by: Skipper ]

[Mattias]

Skipper..

Those are very nice and unusual pictures indeed, the last two that is. where did you get them?

M.

[offtaskagain]

The title of "Zvierboy" belongs to SU-152, not 122. It means animal hunter, in regards to its ability to hunt tigers, panthers, and elefants. The SU-122 wasn't much of a tank killer, being similar in role to the Sherman 105s. The ISU-122 on the other hand, was an excellent tank killer.

[Matthew_Ridgeway]

USER Said: BTW whats that tube attached to the side of the vehicle? Not the extra fuel tank in the back but the one next to the fighting compartment?

I think the Germans referred to those “tubes” as “Kletterbalken” (at least according to Jean Restayn's work on Tigers on the Eastern Front). Some of us might refer to that “tube” as a log. Very loose translation of “Kletterbalken” is crossing beam…or as Makjager has astutely indicated: it is a unditching beam/log. Quite a common feature on AFV's on the Eastern Front. Common that is, if one takes the number of pictures one comes across of Tigers, T34’s, Panthers, etc with logs or heavy lumber draped on the sides of their vehicles as an indication. Russian tankers were also apparently fond of carrying fascines for filling in "problem" ditches.

[Username]

This courtesy of our good friends at the ru site..

The vehicle may have been the biggest baddest rusky stuggy but its armor may not have been up to the challenge of medium ranges.

Slow rate of fire, low ammo load, big target, etc. I dont think its the uber-monster some think it is. Better than a Brummbar for sure though.

Lewis

[Matthew_Ridgeway]

Skipper Said I think you stated that ISU-152 had rate of fire something like 1 shot in 1.5 minute. I have a contradicting informtion,. Namely:

I would have to agree that 1 round per 1.5 minutes seems pretty damned slow even for a weapon with a 40kg AP shell. I’m digging through some alternate sources to see if I can’t come up with some additional corroborating information to what you’ve already presented.

So far: Wolfgang Fleischer’s: “Russian Tanks and Armored Vehicles, 1917 – 1945” (pg 163) indicates that the ROF for the Soviet 152mm Tank Howitzer model 1938/40 was 2 rounds per minute.

[JasonC]

Some perspective on the ROF of such large guns, rated and actual. They are two different things. The gun on this thing is essentially the same as on the M-109 self-propelled 155mm howitzer used in the US army today - the standard SP artillery piece.

I've used those, and can provide some details. The shell weighs almost 100 lbs, and the powder loads in seperate bags. The shell has to be rammed home with a hydraulic press that swings down from the ceiling. The breach closes with a screw-type seal, but is forced most of the way closed by a powerful spring-release - you just have to finish closing it with a lever. The shell is primed by a seperate cartridge loaded behind the breach, and the mechanism there slides over to shut the "touchhole" effectively.

All of this is done by one loader standing in a confined space, bending to reach the shells out of the ammo holder, etc. Somebody else has already fused the shells, though, so that step was done well before firing. There is a long sequence prescribed for the whole loading and firing process. And the rated ROF of the M-109 in the manuals, is 4 every 3 minutes, or 45 seconds per shell.

I'm not any good at it particularly, never was, and spend most of my time on a different piece, the M110 8", which is open topped, uses more hydraulics to do everything because the shell is twice as heavy, etc. But I could still fire an M-109 in 15-20 seconds, or 3-4 rounds per minute, which is 2-3 times the rated ROF. Was I being careful, doing that? No. Was it tiring? Yes. But it was no great feat - most experienced gunners could.

You've got a 6 or 8 round mission and you get them through. Then you rest. Things you have done enough just do not take much time. The slowest part was the ramming, because it depended on the speed of the machinery and could not be pumped faster by sheer adrenline. Everything else could be and was.

[Michael Emrys]

Steve can correct me, but I think what he actually posted was 1.5 rounds per minute, not the other way around. That figure is much closer to the 2 rpm quoted here, which could have been arrived at by rounding up anyway.

Several people on this board have been extolling the ISU-122 as a tank killer, but it has been my impression that that honor more properly belongs to the SU-100 because it had a higher velocity gun. So, does anyone have any actual penetration stats on both weapons? It's interesting to note that it was the SU-100 that remained in service long after the war. I think Egypt still had a battalion of them in the 1973 war.

Michael

[offtaskagain]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Michael emrys:

Steve can correct me, but I think what he actually posted was 1.5 rounds per minute, not the other way around. That figure is much closer to the 2 rpm quoted here, which could have been arrived at by rounding up anyway.

Several people on this board have been extolling the ISU-122 as a tank killer, but it has been my impression that that honor more properly belongs to the SU-100 because it had a higher velocity gun. So, does anyone have any actual penetration stats on both weapons? It's interesting to note that it was the SU-100 that remained in service long after the war. I think Egypt still had a battalion of them in the 1973 war.

Michael<HR></BLOCKQUOTE>

The SU-100 was a better tank killer, but there were far fewer of these produced, as the 122 could already kill everything short of a Maus.

[hellfish]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Michael emrys:

Several people on this board have been extolling the ISU-122 as a tank killer, but it has been my impression that that honor more properly belongs to the SU-100 because it had a higher velocity gun. So, does anyone have any actual penetration stats on both weapons? It's interesting to note that it was the SU-100 that remained in service long after the war. I think Egypt still had a battalion of them in the 1973 war.

Michael<HR></BLOCKQUOTE>

China used to have SU-100s in the tank/assault gun regiments of their Group Armies until about 1987. They have since been replaced, but kept in storage, in favor of an indigenous 120mm assault gun.

[Matthew_Ridgeway]

"Michael Said: “Steve can correct me, but I think what he actually posted was 1.5 rounds per minute, not the other way around. That figure is much closer to the 2 rpm quoted here, which could have been arrived at by rounding up anyway.”

Or perhaps it was rounded down from the 2 to 3 rounds per minute indicated in Skipper's initial post.

I'm more inclined to buy into Jason's logic regarding firing a mission\engagement as quickly as possible...than rest. Experience is obviously a big factor. One merely has to look at contrasts in CAT scores relative to crew experience to see that this is a crucial ingredient in engagement speed.

Layout of ammunition storage is also a big factor. I have no idea how ammunition storage was laid out in the M-109, but ROF goes into the ****er if the ready-rack right behind the loader is empty from firing previous engagements. The crew now has to fish around for rounds stored in less convenient locations of the track.

As far as penetration stats are concerned it seems to me APG conducted firing tests with a D25T back in the 50’s. Perhaps testing was also conducted on the D25S as well. APG has however purged much of its old archive information from the 40’s and 50’s…”shredder” or “round filed”. The Germans were also pretty hot on conducting firing tests with captured ordnance for obvious reasons. Perhaps a visit to the Bundesarchives might be fruitful (assuming of course that documentation was not absconded by the British and Americans after the war)

Or you can always fall back on calculated penetration values you see spread all over the Internet. Why rely on actual test firing data when you have Milne-de-Marre.

[ 06-04-2001: Message edited by: Matthew_Ridgeway ]

[Username]

http://history.vif2.ru/library/archives/weapons/weapons4_01.html

Heres a good comparision. I would have opted for the 100mm myself.

I cant believe the 152mm could have as high a velocity as the website claims. Something like 650m/s?

Lewis

[Triumvir]

Don't forget that the 100mm D-10T is the same gun that's in use on the T-54 family. A _really_ venerable piece of work.

As far as I know, the only M1 disabled by enemy action (as opposed to mines) in the Persian Gulf was hit by a D-10 in the rear. Anyone have more information on that?

[Amedeo]

The ROF of the SU/ISU-152 was surely dependent on ammo layout but consider that also the two loaders come into play. I'm not actually sure about this fact but on the SU-152 page of the Bronia website there's a list of the crewmembers and that is: commander, aimer (gunner), loader, ??? and driver-mechanic. My Russian is not so good so I couldn't tell what the guy listed after the loader does but my guess is that he's a 2nd loader (the AFV has no bow MG so there's little he can do in combat).

Fow what concernes the relative performances of the 100mm, 122mm, and 152mm Soviet guns, well actually the 100mm had superior armour piercing performances _against vertical armour_ but the blunt nose 122mm APBC round fared better against sloped armour being able to rip trough the Panther frontal glacis at 2000m, while the 100mm could have performed better against the Tiger. Anyway to have guns able to frontally destroy Panthers and Tigers at medium/long ranges is a dream in CMBO terms. The problem is to hit them!

Regards,

Amedeo