The 1077th Anti-aircraft Regiment under Colonel Raiynin, was a unit of the Stalingrad Corps Region of the Soviet Air Defence Forces which fought during the Battle of Stalingrad in 1942. The Stalingrad Corps Region was part of the Stalingrad Military District and later subordinated to the Stalingrad Front during the battle for the city. The regiment, like many of the anti-aircraft units, was made up almost entirely of young women volunteers, barely out of high school. They are mostly known for their bravery in the defense of Stalingrad (now Volgograd), when they engaged an advancing Panzer unit by setting their guns to the lowest elevation and firing them directly at the advancing tanks.
English-language sources about this unit are sparse and contradictory. What seems clear is that, like most of the anti-aircraft units, they were poorly trained and under-supplied with ammunition. They probably did not have armour piercing rounds, but rather fragmentation 'flak' rounds, and it is questionable how effective these would have been against armour. Their guns were M1939 guns which were 37mm copies of Bofors.
In the documentary "The Stalingrad Apocalypse" (which interviewed many survivors) a surviving German trooper, in old age, recalls that he had been part of the advance unit of Germans and said that they had "over-run" the female gunners without any effective resistance. He said it was his first ever engagement with female soldiers.
1077th Anti-Aircraft Regiment (Soviet Union) Wikipedia
On August 23, 1942, the German 6th Army launched its offensive on Stalingrad. After extensive bombing which turned much of the city into an inferno, the 16th Panzer Division advanced unresisted until it reached Gumrak airport, 15 km northwest of the city, where the tanks came under fire from anti-aircraft guns.
The 16th Panzer Division recorded that "right until afternoon we had to fight 'shot for shot' against 37 anti-aircraft positions manned by tenacious fighting women, until all were destroyed".
This passage is repeated in a number of places out on the internet:
The first combat with a German Panzer column occurred on the approaches to the Tractor Factory. The unit involved was the 1077th Anti-Aircraft Regiment. The crews of these AA Guns consisted of young girls who had volunteered for combat duty with the Army. The Artillery unit was positioned on the flat ground of the Steppe. We saw that they were all alone as there were no Soviet troops either to the left of them, or to the right. We fully understood that it was their duty to stand and defend this ground to the last person living.
The young female gunners have stopped the German Panzer Column. We see in front of us that there are several 'Panzers' and trucks ruined and burning. They had taken their time in planning this attack and used small battlegroups that tried to make a lightning attack to quickly take out our positions. The Germans attacked several times inflicting heavy losses to this unit and they kept attacking until all were killed. The dead will remain forever scattered in the steppe as a testimony of their heroic defence of our factory.
There is no indication as to its source beyond The Volgograd archives. It is unclear whether this is at Gumrak (as perhaps the mentions of the steppes indicates) or closer into the city, where the factories would have been. The tractor factory (which was then producing tanks) was a major objective of the invading forces.
The Soviet official history of the war also makes mention of this action:
The anti-aircraft troops first engaged the Panzers on August 23rd on the northern outskirts of the city. An attack from this quarter by the enemy had been unexpected, and so there were no rifle units in position to assist the batteries of the 1077th Anti-Aircraft Regiment in their defense against the strong concentration of German tanks and motorized infantry. Under the command of Colonel W. S. German, for two days the regiment fought alone and repelled the assaults of German submachine-gunners. During the combat, the regiment destroyed or damaged 83 tanks and 15 other vehicles carrying infantry, destroyed or dispersed over three battalions of assault infantry, and shot down 14 aircraft.
The 1077th Anti-Aircraft Regiment remained in service with the Soviet forces to the end of the war. In May 1945, the regiment was part of the 86th Air Defense Forces Division, itself subordinated to the Southwestern Front. In 1945, the 86th Division was charged with air defense support for the Kharkov and Odessa Military Regions, and also for the Independent Coastal Army.