Wonder Bullet

"Act

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:

1. Stock rounds with B-32 bullets.
2. Rounds with 3.15 grams of propellant and a metallic-ceramic core.
3. 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
	21	3	13	21	95.2
Experimental round with metallic-ceramic bullet (w=4.2)	5	3		2	100

Notes:

1. Dents on one side, no effect on the other side.
2. Three hits caused bulges on the rear side, two had the bullet tip penetrate completely.
3. 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.

Conclusions

1. The effectiveness of the experimental OTB NKVD rounds is superior to all currently known 7.62 mm armour piercing incendiary bullets.
2. 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.
3. 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.
4. 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.
5. Calculate the propellant load with the aim to produce average pressure less than 3200 kg/cm^2 as both rounds tested had similar results."

RGASPI 664-1-1

AK Muzzle Devices

The accuracy of an automatic weapon is important, and many experiments were run on the AK platform to figure out if it can be increased. A number of experimental muzzle devices were built for this purpose. _tezka provided this picture.

Left to right: similar to stock type, brake-compensator, two chamber, flash suppressor, single chamber, reactive.

While all of these successfully reduced muzzle climb and improved accuracy, there was one important drawback that engineers did not necessarily consider...

"The positive effect of the muzzle brake on the accuracy is at odds with the negative result of the sound wave hearing, which is greatly increased to unacceptable levels with most muzzle brakes.

...

The evaluation of the effect of the sound waves on hearing reveals that all muzzle brakes in the table result in a bothersome or painful sensation in the ears."

A DShK style reflector was considered to remedy this effect, but...

"...a reflector of such size can hardly be recommended as they decrease the maneuverability and comfort of the weapon and do not achieve the intended result of reducing the sound to a level that does not cause pain."

Another device was tested to improve accuracy, but it was a different kind of brake.

Curiously enough, it was a brake for the bolt. The experiment was meant to determine the effect of the speed of the bolt flying back and forth on accuracy. The knobs on the sides could adjust the force applied to the bolt in order to slow it down.

AK Precision

"Characteristics of dispersion for Kalashnikov assault rifles (AK-74 and AKS-74)

Bullet with a steel core

Shooting in short bursts, while prone"

The table is split into two sections. The section on the left is for a well trained shooter, the section on the right is for an average shooter. For each section, the dispersion is first given for the first bullet in the burst (height, then width), then for the subsequent bullets. The first two columns in the subsequent section are for the bullet itself. The second two are for the average point of impact between all hits. The last two columns are the total dispersion.

The notes in the bottom remark that the table is also valid for shooting at night, within the range of the night vision scope, and when firing single shots, the dispersion in the first two columns (first bullet of burst) is valid.

Sturmgewehr Usage

Some of you may have wondered when the Soviets noticed that the Sturmgewehr has joined the arsenal of German infantry. Wonder no more! Via kris-reid:

"To the People's Commissar of Defense, Marshal of the Soviet Union, comrade I.V. Stalin:

Since the Spring of this year, forces of the Kalinin, and then Volkhov and Leningrad Fronts have captured, among other weapons, several specimens of new German automatic 7.92 mm carbines, which are a new type of infantry weapon that has not been previously used by the Germans in large amounts until recently."

The date on this document is April 16th, 1943. Here's the intel obtained on this mysterious weapon:

"Enemy tactics and technology

Engineer-Captain Ya. Krutik

1. New German handheld machinegun

The German army has recently adopted a new handheld machinegun, using an intermediate round (an average between a rifle round and a pistol round). The machinegun's designation is "MK belash 42 (H)". The automatic mechanism is driven by redirection of gases through an opening in the barrel.

The machinegun can fire automatically or in single shots, for which a switch is present in the trigger guard, next to the pistol grip.

The machinegun is fed with a box magazine, which holds 35-38 rounds.

• Caliber: 7.9 mm
• Length: 935 mm
• Mass: about 5 kg
• Round mass: 16.8 g
• Bullet mass: 8.2 g"

The translator was a little presumptuous. "MKb" stands for Maschinen Karabiner, or machine carbine. Also, the magazine capacity has grown somewhat from the 30 rounds it actually contained. Otherwise, this intelligence is correct.

High Capacity

I am sure that many of you have seen those comedic 100-round magazines for AK assault rifles that can barely feed 5 or 6 without jamming up. What you probably didn't know is that the idea isn't exactly new.

These photos are from magazine trials of 30, 40, 50, and 100 rounds. 

Precision Comparison

In 1948, it was clear that the PPSh has served its time, and a new, more powerful automatic infantry weapon was necessary, using an intermediate 7.62x39 mm mod. 1943 cartridge. Several weapons were designed to Tactical-Technical Specification #3131 and tested along with their submachinegun ancestor and the German Sturmgewehr for comparison.

The columns represent the radii of dispersion for bursts while prone and single fire while prone. R100 gives the full radius, and Ч50 gives the mean radius. The rifles are as follows:

• AS-44 type 7 (with 3 vent openings)
• AS-44 (no changes)
• Kalashnikov assault rifle
• Dementyev assault rifle
• Bulkin assault rifle
• Korobov assault rifle
• Submachinegun model 1941 (PPSh)
• MP-44 (Sturmgewehr)

And the last row is the precision requirement. The summary reads:

"The AS-44 with vent openings (type 7) surpasses all other assault rifles: in Ч50 by 2-4 times, and in R100 by 2.3-7 times. The precision when firing in full auto mode matches requirements."

It is also interesting to note that the famous Kalashnikov made the list. Despite being less precise than the modified AS-44 and failing TTT#3131, the weapon surpasses the Sturmgewehr in all criteria except single fire mode while prone, where the latter has a slight advantage.

Science Fiction

Sometimes, inventions that are sent in to the military seem pretty impressive. Like this one!

"Comrade Lyadov proposes a super-speedy anti-tank rifle, where the propellant burns as fast as possible, and the bullet is propelled primarily through adiabatic expansion of gases. In order to achieve acceptable pressures, the inventor uses low propellant density. With heavy projectiles, the inventor hopes to maximize the Pcp/Pm ratio and achieve muzzle velocity of 3400 m/s.

In order to achieve a chamber large enough, which the inventor says will need to be bigger than the size of the rifled section of the gun, the inventor proposes a two-piece chamber. One of them is a regular chamber, another, connected to the first, is underneath the barrel. The propellant, as can be assumed from the proposal, all fits in the first chamber."

3400 m/s! Pretty impressive. Of course, there is always a catch.

"When evaluating comrade Litvinov's proposal, it must be noted that the aforementioned muzzle velocity (3400 m/s) was obtained after making critical mistakes in the calculations, which makes the ballistic portion of his project a sad misunderstanding."