On July 6th, 1941, based on the orders of the OTB chief, Major of State Security comrade Kravchenko and GAU KA chief, Colonel-General comrade Yakovlev we, [long list of commission members] performed trials of 7.62 mm AP-I bullets with a ceramic-metallic core and gunpowder developed by the OTB NKVD at the OTB NKVD proving grounds to establish their effectiveness.
Experimental rounds of two types were submitted for trials. One type had 4.15 grams of propellant, the other 4.2 grams. Characteristics of the rounds are shown in attachment #3.
Trials were performed against 20 mm surface hardened armour (see characteristics in attachment #1) with the air temperature of 28-29 degrees and range of 100 and 150 meters.
The following bullets were used to test the quality of the armour plate and compare the effectiveness of experimental bullets:
- Stock rounds with B-32 bullets.
- Rounds with 3.15 grams of propellant and a metallic-ceramic core.
- Rounds with 4.2 grams of experimental gunpowder and B-32 bullets.
These bullets were fired at 50 meters, as firing them from larger ranges made no sense due to their ineffectiveness against 20 mm of surface hardened armour from even 50 meters. Results are contained in the following table:
|Hits||Complete penetrations||Incomplete penetrations||Complete penetrations, part of bullet is stuck||% penetrations|
|Stock round with B-32 bullet||5||0||51||0|
|Experimental round with B-32 bullet||5||0||51||0|
|Experimental round with metallic-ceramic bullet (w=3.15)||5||0||52||0|
|Experimental round with metallic-ceramic bullet (w=4.15)||5||3||2||100|
|Experimental round with metallic-ceramic bullet (w=4.2)||5||3||2||100|
- Dents on one side, no effect on the other side.
- Three hits caused bulges on the rear side, two had the bullet tip penetrate completely.
- The bullet tip penetrated completely.
In order to test the incendiary action of the bullets, experimental rounds (w=4.2) were fired from a range of 150 meters at a 20 mm plate with a full gasoline tank up against it. As a result, the gasoline ignited from the first shot that hit the gasoline (the first shot that was fired hit above the gasoline). Both bullets penetrated the armour completely.
- The effectiveness of the experimental OTB NKVD rounds is superior to all currently known 7.62 mm armour piercing incendiary bullets.
- The results should be immediately checked at NIPSVO to establish ballistic norms and more carefully establish the armour penetration effectiveness. For this purpose, USV GAU should produce 500 bullets with ceramic-metallic cores by July 6th, 1941, and OTB NKVD must assemble them and send them to NIPSVO by July 7th, 1941.
- Due to good results of trials, do not wait for NIPSVO trials to complete and begin production with existing propellant. USV GAU must provide the bullets for this batch. The batch must be complete by July 15th, 1941.
- NKO must give the order to NKB for production of the gunpowder developed by the OTB NKVD at factory #40 in the amount of 7-10 tons, and NKV must set up production of 7.62 mm bullets with ceramic-metallic cores at factory #188.
- Calculate the propellant load with the aim to produce average pressure less than 3200 kg/cm^2 as both rounds tested had similar results."