The 'Slow' Soviet D-25T 122mm That Crushed 3rd SS Totenkopf's Panzers In Budapest's Last 14 Days

Added: 2026-06-02

[00:00:00]On the 18th of January 1945, the most feared armored fist in the Vafen SS rolled out from south of Lake Balaton with one job. Punch through the Soviet ring. Reach Budapest. Save tens of thousands of trapped Germans and Hungarians dying inside the encircled city. The fist was the fourth SS Panza Corps under Herbert Ottogila, two veteran Vaffan SS Panza divisions. Third SS Panza Division Totenov on the right.

[00:00:31]Fifth SS Panza Division Vicking on the left. Panthers and Tigers that had killed Soviet armor from Karkov to Warsaw. Crews who had survived 2 and 1/2 years of the worst meat grinder in human history. Men the Red Army feared by name. 9 days later, 25 km short of the city, the whole attack was a smoking line of dead tanks on a Hungarian road.

[00:00:57]It was not killed by infantry. It was not killed by air. It was killed by a gun the SS Panza arm had openly mocked for a year. A gun so slow its crews could only fire two or three shells a minute. A gun lifted off a 1931 core artillery piece and shoved into a tank turret by a man working out of a converted artillery shop in Sedlossk.

[00:01:21]The Soviet D25T 122 mm mounted on the IS-2 heavy tank.

[00:01:29]This is the story of how the slowest tank gun on the Eastern Front ended the careers of more Totten Panza crews than any other Soviet weapon in the war.

[00:01:39]Budapest, Hungary. December 26th, 1944.

[00:01:44]On that day, Marshall Rodon Malinowski's second Ukrainian front and Marshall Fodor Tolbukin's third Ukrainian front shook hands west of the city. The road to Vienna was cut. The capital of Hungary was sealed. Inside the pocket sat the first Hungarian army, the 9inth SS Mountain Corps, German garrison troops, Hungarian Jearmms, and 800,000 civilians. Hitler refused to let any of them break out. Buddhapest was to be held to the last man, the last shell, the last frozen loaf of bread. To save them, the German high command turned to the only formation in southern Europe still strong enough to drive through a Soviet front. The fourth SS Panza Corps Gila's corps was the German army's emergency fire brigade. Totenov and Vicking had stood up the eastern front at Karkov. They had bled the Soviets white at Warsaw. Now they were yanked off the Vistula, loaded into rail cars in the middle of winter and shipped 600 km south to Lake Balaton with one mission. rip a hole through Tolbukin's third Ukrainian front and reach the trapped garrison before it starved. The core came under the command of General Herman Balk's sixth army supported on the left by the third Panza core. Three separate relief attempts were planned.

[00:03:09]Three swings of the same hammer. The first swing was operation Conrad 1. It started on the 1st of January 1945, launched out of the Tata region. By the 6th of January, it was dead at the foot of the Gretcha Hills. Halted near Bitska and Jeambbeck by Soviet anti-tank fire.

[00:03:29]It could not crack. The second swing was Conrad 2. It started on the 7th of January. Launched from Estagom along the Pillis ridge line. By the 12th of January, the SS Panza Grenadier Regiment Westland had reached Pilisent 20 km from Buddha. 20 km. The men inside Budapest could hear the guns and then Conrad too stalled too. The terrain was impossible.

[00:03:57]The Soviet defense was deeper than expected and Gila had to pull back before the spearhead was cut off. So the planners loaded everything that was left into a third attempt. Conrad 3, the largest of the three. The one that had to work because there would not be a fourth. Now you have to understand what the Soviets had waiting for them on that third attempt. By mid January 1945, Tolbukin's third Ukrainian front was thinly stretched along the market line west of Budapest. The fourth guard's army held the most exposed sector with infantry towed anti-tank guns and a handful of armored reserves. Behind them sat the heavy tank regiments, independent regiments built around a single weapon, the IS-2. The IS-2 was a 46tonon monster, cast steel turret, smooth and rounded like a river boulder, steeply sloped frontal armor, 90 to 120 mm thick. And in that turret, a gun that broke every rule the German Panzer arm believed in. The D25T was designed by Fodor Fodorovich Petrov, head of the artillery experimental design bureau at factory number nine in Sedlossk.

[00:05:14]Petrov had taken over the bureau in 1940 when it was still part of the giant Ural Mash works. In 1942, the artillery operation was carved out as a separate plant given the bare designation factory 9 and Petrov was named chief designer.

[00:05:33]He was a quiet man, an artillery engineer who had grown up working on towed core guns. And he believed the German Tiger problem had a simple answer. Hit it harder than it could hit you, even if you only hit it once a minute. His answer was not a clean sheet design. It was a tank adaptation of the A19, a Soviet core artillery piece from 1931.

[00:05:58]The A19 had been a long range deep echelon weapon dragged into firing position by tractors and dug in for siege work. The Germans had captured A19s by the hundreds in the early years of the war and stockpiled them as towed guns, mostly using them to lob shells across rivers in the east. Nobody on the German side believed that a piece that old, that heavy, that slow could be useful inside a moving tank. That belief is what killed Toten Cop. Petrov shortened the A19 tube, modified the breach for tank use, kept the original ballistics, and handed the design to the IS heavy tank program. The man who took it from there was Ysef Yakovich Cotton, the head of SKB2, the heavy tank design bureau at the Chelabinskira plant.

[00:06:53]Cotton had been the chief designer of the pre-war KV1 and KV2 heavy tanks.

[00:07:00]After the German invasion, he had been evacuated east with the Lenenrad Kiraov works in 1941 and his bureau had become the brain of the giant Eural tank factory the Soviets called Tankrad, the largest armored vehicle production complex on the planet. In the middle of 1943, Cotton's team built the prototype that became the IS-2.

[00:07:24]They called it Object 240.

[00:07:27]They tested two competing main guns, Petrov's D25T and a sleeker, faster firing 100 mm, the D10.

[00:07:38]The choice came down to a single test.

[00:07:40]Both guns were fired at a captured Panther parked on a Ural range. The 100 mm cracked the turret face. The 122 ripped it off. The decision was made.

[00:07:53]Yes, the rate of fire was lower. Two to three rounds a minute against five or six. Yes, the ammunition was separate loading, projectile and propellant in two pieces, handfed by one exhausted loader in a cramped turret. But one good shell from the D25T did more damage than three from a 100 mm. And against the German cats, more damage per shot was the only thing that mattered. In January 1944, 2 weeks after the IS-2 entered series production, Fodor Petro was named a hero of socialist labor. By the end of the war, his factory number 9 had pushed gun after gun into Soviet service, and his tank version of the A19 had become the most feared heavy gun on the Eastern Front. Production of the IS-2 ran from late 1943 through the end of the war.

[00:08:49]Chelabinskirov pushed out 35 tanks in January 1944, 75 in February, 150 in April, and over 225 a month from July onward.

[00:09:03]By V-Day, the plant had built more than 3,800 IS-2s.

[00:09:09]The workforce at Chelabinskyov swelled to 60,000 people. Half or more were women working three shifts, sleeping on factory floors, hand fitting tank turrets in a cold so deep the breach grease froze on the assembly line.

[00:09:26]That was the machine waiting for Toten Cop at Baton. The D25T fired the BR471B, armor-piercing ballistic capped high explosive filler. The kind of shell that does not just punch a hole through armor. It punches a hole, then detonates inside the crew compartment.

[00:09:47]The numbers from the German Wroof One test office tell the story. Wroof 1 tested everything they captured. They tested the IS-22 and their own report concluded that the D-25T would penetrate the front of a Tiger 1 between 500 and 1,500 m. At Kubinka, Soviet engineers ran the same test on a captured Tiger they had hauled back from the front. They confirmed it.

[00:10:16]Frontal turret kill at 1,00 to,500 m.

[00:10:20]Weld seam kill on the lower hull at 500 to 600 m. From the side, a Panther was vulnerable to the BR471B at well over 2 km. That meant a Soviet IS-2 sitting in a hull down ambush in the snow could kill a tiger or a panther from a range where the German gunner could not even see the muzzle flash through the storm. And in January 1945, the snow never stopped. January 18th, 1945, zero hour. The fourth SS Pansor jumped off from south of Lake Balaton. Toten from the right, Viking on the left. The third pancer core in support to the north. Panthers and tigers running on frozen mud. Low clouds overhead. The temperature near zero. Visibility cut to a few hundred meters by snowstorms blowing in off the Hungarian plane. For the first 48 hours, it looked like a German classic. Gil's spearheads tore through the Soviet fourth guard's army.

[00:11:23]They overran towed anti-tank positions.

[00:11:26]They crushed infantry trenches under track and shell. Soviet tank crews fell back in confusion. By the end of the first day, a German breach 30 km wide and 60 km deep had been torn through Tolbukin's line. By the morning of January 19th, lead elements of the fourth SS Panzacore reached the Danube, splitting the Soviet forces in Trans Denonia in half. Hundreds of Soviet tanks burned along the road. 400 km of ground had been recaptured in 4 days.

[00:11:59]Inside Budapest, the trapped garrison heard the gunfire to the southwest and counted the hours. But this was the part everyone missed at the time. Tolbukin had not committed his real anti-armour reserve. The IS-2 heavy regiments were still pulling back, repositioning, finding the ground they wanted. Soviet defensive doctrine on the third Ukrainian front had been hammered into shape over two years of Eastern Front fighting. The infantry and the towed anti-tank guns up front were not the main line of resistance. They were the bait. They were there to slow the German spearhead, force it to deploy and channel the lead tanks down a specific axis. The real killers, the IS-2 regiments, were always held one terrain feature back, parked in farmhouses behind hedgerros in the lee of a low rise with overlapping fields of fire and pre-measured ranges to every roadbend in front of them. They were not going to fight Toten Cop at speed on open ground.

[00:13:00]They were going to fight Totenop on terrain they chose, at the moment they chose, with the first shot they chose.

[00:13:07]By the afternoon of January 19th, the Soviet high command had identified the German Axis. Stavka released reserves to Tolbukin overnight. The 30th rifle corps, the 54th rifle corps, and the 23rd tank corps were ordered forward.

[00:13:23]The fifth guard's cavalry corps with 100 tanks, 360 artillery pieces, three anti-tank gun regiments, and six artillery regiments was thrown into the gap. They marched 60 km in 24 hours in winter on icy roads and arrived on January 20th. And in front of them, dug in along the side roads and tree lines between Skkeshavar and the Budapest pocket, the IS-2 regiments were already waiting. That was the moment Operation Conrad 3 stopped being a German offensive and became a German graveyard.

[00:14:00]Picture the ground in your head. Snow fields broken by orchards and frozen ditches. Single track village roads with high embankments on either side. Stands of bare timber. Low farm houses with brick walls. Visibility on a good morning 6 to 800 m. On a bad morning, less than 200. The Panther and the Tiger were built to fight at long range across open step. The IS-2 and the D25T were built to fight at the range where you could see the man you were killing. And in that ground, the slow gun became the fast gun. A Toten Cop Panther rolled around a bend at 400 m. The IS-2 hullled down behind a low rise in the snow had been zeroed on that exact bend for an hour. The Soviet commander had picked the spot the day before. The gunner had laid the brereech, checked the elevation, and waited. The loader had a ready rack of six BR471B shells stacked by his knee. One shell from the D25T, the Panther's turret face cracked. The round went through. The high explosive filler detonated inside the fighting compartment. The tank shuddered, slewed sideways, and caught fire. The commander in the cup was dead before his body hit the deck plate. The next panther in line break and tried to back up. The road behind it was packed with vehicles, halftracks, fuel trucks, a recovery vehicle. There was no room. The second IS-2 shell hit it in the lower glassy right at the weld seam. Same result. The hull split. The ammunition cooked off.

[00:15:44]The turret lifted off its ring in a column of black smoke 100 ft high. Now the road was blocked. The third panther tried to push out into the ditch to bypass the burning wrecks. The frozen ground was too hard. The ice broke under the tracks. The tank through a track and stopped. The crew bailed out and ran for the treeine. They never made it. A Soviet infantry section had been waiting in the ditch the entire time. 2 minutes, three tanks destroyed. The IS-2 had fired six shells. The Panthers had not fired one. They had never even acquired the target. That was the pattern repeated across the relief axis across 14 days. At Pent, at Abba, at Serigelius, at the rail crossings outside Seeshvar, at every single road junction where a toten cop column tried to push north toward Budapest, an IS-2 regiment was already waiting in the trees with the gun loaded. Read that again. The most feared Panza crews in the Vuffan SS in the best heavy tanks the Reich could build lost the jewel because the slow gun got the first shot from a thousand m away and one shot was all it took. By January 22nd, Totenkov's armored core was being bled away tank by tank. The core was still pushing forward, but for every kilometer gained, another Panza was lost. And in this fight, the loss rates worked the wrong way. Germany could not replace a Panther in 24 hours.

[00:17:21]The Red Army could replace an IS-2 in a day because the conveyor at Chelabinskira never stopped. A toten cop afteraction report from late January preserved in captured German records put the problem in plain language. Russian heavy tanks were engaging from 1,800 m with 122 mm guns. The Panthers could not reply effectively at that range. The losses in lead elements were now severe.

[00:17:49]Severe is a clean word for what was actually happening. SS Panza commanders, men who had survived Kursk and Karkov and the long retreat across Ukraine, were dying in their turrets because a Soviet artillery piece from 1931 had been shoved into a tank and was now killing them at a range where they could not even fight back. I mean, think about that for a second. The core tried to find a way around. Gil shifted weight.

[00:18:17]He pushed Viking forward on a new axis.

[00:18:19]The result was the same. Wherever the German Panthers and Tigers tried to advance, the IS-2s were already in position, hull down, waiting. With the D25T pre-amed on the most likely choke point, the Soviet defense was no longer a line. It was a series of nested kill boxes, each one designed around a single IS-2 regiment with infantry and anti-tank guns filling the gaps between.

[00:18:47]January 25th, 25 km from Budapest. The fourth SS Panza Corps was running out of running tanks. The infantry was exhausted. The fuel state was bad. The temperature dropped again overnight.

[00:19:01]January 26th, Soviet reinforcements were piled in along the last 15 km. The road forward was a kill zone of dugin IS-2s, anti-tank guns, and mechanized infantry.

[00:19:16]Gil requested permission to halt and consolidate. Permission was denied. He halted anyway. There was nothing left to push with. January 27th, Tolbukin opened his counter offensive with three mechanized core and one rifle core aimed at encircling the lead German elements.

[00:19:35]Operation Conrad 3 was officially over.

[00:19:39]The core had not reached Budapest. It had not even seen Budapest. It had been stopped by an obsolete artillery piece in a tank turret fired by crews who knew exactly how to make two rounds a minute hit harder than eight. By the end of January, Viking and Toten together had suffered 8,000 casualties, including 200 officers. The German Sixth Army had lost 164 armored vehicles across the three Conrad operations with more than 70 wrecks abandoned on the field because there was no fuel or recovery vehicles to drag them home. Inside the city, the garrison waited two more weeks.

[00:20:20]On the night of February 11th, the surviving defenders launched a breakout attempt toward the German lines.

[00:20:27]Roughly 30,000 men tried to fight their way out through the suburbs of Buddha.

[00:20:33]Of those 30,000, only 785 reached friendly territory.

[00:20:40]The rest were killed, wounded, captured, or scattered in the hills west of the city.

[00:20:46]On February 13th, 1945, Budapest fell.

[00:20:51]The first Hungarian army was destroyed.

[00:20:54]The 9inth SS Mountain Corps was destroyed.

[00:20:58]According to the historian Christian Unvari, the most thorough chronicler of the siege, 38,000 civilians died inside the city. 13,000 from military action, 25,000 from starvation, disease, exposure, and the mass executions carried out by the Hungarian Arrow cross.

[00:21:20]The Soviet forces had paid for the city with somewhere between 100,000 and 160,000 of their own casualties, and the fourth SS Panza, the German army's last fire brigade, never recovered.

[00:21:36]Toten would fight on, but as a depleted shadow of the formation that had rolled out from Balaton in January.

[00:21:44]By April, the division was retreating into Austria. By May, it was gone.

[00:21:51]Now, here is the part that almost no one talks about. The D25T did not just outlast Totenov. It outlasted the entire Cold War.

[00:22:02]The gun stayed in Soviet service for decades. It was mounted on IS-2 heavy tanks shipped to Korea in the early 1950s, used by Chinese crews against American forces along the Yaloo River.

[00:22:17]It was rolled into Budapest a second time in November 1956.

[00:22:22]This time by Soviet crews, crushing the Hungarian uprising with the same 122 mm gun, firing into the same streets where Totenop had tried to break through 11 years earlier.

[00:22:36]Hungarian rebels with Molotov cocktails fought IS-2s in the same intersections where their fathers had watched Soviet tanks roll past. In 1945, the IS-2M, an upgraded post-war rebuild with better optics and a stabilized gun, was still in active Soviet reserve in the early 1990s, almost 50 years after Conrad 3.

[00:23:04]Variants and derivatives of the D25T served in the Middle East into the 1970s with Syrian and Egyptian crews firing the same separate loading drill Petrov had designed in a freezing spurloofs workshop in 1943.

[00:23:21]Cuban crews trained on the IS-2.

[00:23:25]Chinese tank schools still drilled on the loading rhythm into the 1980s.

[00:23:31]a 1931 artillery piece pushed into a tank in 1943, still serving 60 years later.

[00:23:39]You can walk into a museum today in Moscow, in Warsaw, in Prague, in Kubinka, and stand in front of an IS-2 with the D25T still in the turret.

[00:23:52]The same gun that broke Toten Cop in 14 days outside Budapest is still there, cleaned, restored, displayed under spotlights. A 16 ft barrel of cold gray steel that ended the careers of more SS Panza crews than any other Soviet tank gun in the war.

[00:24:14]The SS Panza arm called it slow. They were not wrong. Two rounds a minute is slow. They were wrong about everything else. A slow gun that hits the way the D25T hit does not need to fire eight rounds a minute. It needs to fire one round well at the right range from the right position against the right target.

[00:24:39]And in the snow and broken ground outside Budapest in January 1945, the IS-2 regiments of the Third Ukrainian front did exactly that again and again for 14 days until the most feared Panza core in the Vafan SS was a smoking line of dead tanks on a Hungarian road 25 km from a city it never reached.

[00:25:06]If you want to see how another Soviet weapon the Germans dismissed as obsolete tore apart an entire SS Panza division, click the next video on screen. And if you made it this far, subscribe. The Eastern Front has more of these stories than most people realize.