The 7.92x24 AE-FMJ cartridge is the civilian version of the 7.92x24 FMJ PDW cartridge. Bouth cartridges have the same performances. The 7.92x24 FMJ is a powerful cartridge which is designed for the use ad mid-range in PDWs. This 7.92x24 FMJ cartridge can also be used in pistols. The 7.92x24 AE-FMJ cartridge can be used for training, target, sport and personal defense shooting. 

This evaluation is conducted based on realistic shooting scenarios derived from the FBI ballistic test protocol. According the FBI ballistic test protocol the minimum bullet penetration is 12” (304.8 mm). The preferred bullet penetration depth is 18” (457.2 mm) and the maximum allowed bullet penetration depth is 24” ( 609.6 mm). Beyond the penetration of 24”, the FBI considered this as over-penetration and not suitable for law enforcement use.

Bare gelatin.

This preliminary test is done at close range with a 7.92x24 FMJ-RN 71 cartridge and a barrel length of 90 mm.

Gelatin block 1 callibration depth 4.5 mm steel BB : 6.5 cm @ 466 fp/sec.

Gelatin block 2 callibration depth 4.5 mm steel BB : 6.3 cm @ 426 fp/sec

In this test the .311 FMJ-RN 71 grains bullet loaded on a 7.92x24 mm cases and fired out a 90 mm barrel and at close range has reached a penetration 610 mm. This is the maximum allowed penetration depth to be acceptable for Law Enforcement use. 

Recovered bullet.

1 layer cotton shirt + bolck calibrated ordinance gelatin.

Some FBI test centers consider bare gelatin not as a realistic test scenario, because bank robbers don’t rob a bank naked. They wear always at least on shirt or T-shirt. We also assume that a burglar will not enter a house naked.

 

This preliminary test is done at close range with a 7.92x24 FMJ-RN 71 cartridge and a barrel length of 90 mm on a cotton shirt and a block calibrated gelatin.

 

Gelatin block 1 calibration depth 4.5 mm steel BB : 6.5 cm @ 466 fp/sec.

Gelatin block 2 calibration depth 4.5 mm steel BB : 6.3 cm @ 426 fp/sec

(Multiple shots fired at the block).

In this test the .311 FMJ-RN 71 grains bullet loaded on a 7.92x24 mm cases and fired out a 90 mm barrel and at close range has reached a penetration depth of 535 mm (21”) .

Recovered bullet.

Heavy clothing + block calibrated ordinance gelatin.

Heavy clothing composition : one layer leatherette jacket + one layer woolen pullover + one layer shirt + one layer T-shirt.

This preliminary test is done at close range with a 7.92x24 FMJ-RN 71 cartridge and a barrel length of 90 mm.

Gelatin block 1 calibration depth 4.5 mm steel BB : 6.6 cm @ 476 fp/sec.

Gelatin block 2 calibration depth 4.5 mm steel BB : 5.8 cm @ 417 fp/sec.

In this test the .311 FMJ-RN 71 grains bullet loaded on a 7.92x24 mm cases and fired out a 90 mm barrel and at close range has reached a penetration 620 mm.

The heavy clothing has increased the penetration depth with 10 mm compaired with bare gelatin. The penetration depth of 620 mm (24.5") out a 80 mm barrel. For Military use this is not a problem. For home defense and law enforcement use this 7.92x24 FMJ-RN 71 cartridge has a litle bit over-penetration. 

 Recovered bullet.

 

2 x 1 mm steel + 2 layers cotton + gelatin.

The is a preliminary test composition derived of the FBI test protocol. The 2 x1 sheets of 20 gauge hot rolled steel test. The set-up is don’t with the materials which where available at the time.

2 sheets of 1 mm thick galvanized steel .

Set-up of 75 mm between the two sheets of 1 mm galvanized steel. 79.88 mm oversize dimension.

+ 2 layers of cotton + calibrated ordinance gelatin.

Fired out a 90 mm barrel at close range. 150 mm distance between the steel plates and the gelatin block.

Impact of the 7.92x24 FMJ-RN (.32 FMJ) bullet at the first steel plate. Hole diameter 9.12 mm

Exit at the second steel plate. Hole diameter 10.86 mm.

Calibrated ordinance gelatin.

Two blocks of gelatin from the same composition behind each other with dimensions 8x11x175 mm.

Gelatin block calibration block 1:  depth 6.4 cm @ 485 fp/sec.

Gelatin block calibration block 2 : depth 5.3 cm @ failure velocity reading

Bullet behavior in the calibrated ordinance gelatin.

 

After the penetration of the 2x1 mm steel plates and the two layers of cotton, the .311 FMJ-RN 71 bullet enters the first gelatin block in a straight position point forwards. The bullet is expanded to a diameter of 10.8 mm.  The biggest disruption in the bullet path is 12 mm wide and is clearly visible over a distance of 170 mm.

Then the .32 FMJ-RN 71 bullet enters the second gelatin block. The bullet path is barly visible and the bullet ends-up at a total depth of 345 mm or 13.58 inch.

The 7.92x24 FMJ-RN cartridge can satisfy the requirements of the FBI ballistic test protocol and achieves in this test the requested 12 “ penetration depth.

Identification of the objects in the gelatin block.

A : Fragments of the second steel plate. The second steel plate was only at a distance of 150 mm from the gelatin block. This is the round out-stamp caused by the Full Metal Jacket Round Nouse bullet.

B :  The 4.5 mm steel BB from the block calibration.

C :  Fragment of the first steel plat. The round out-stamp of the first steel plate is pressed around the bullet and is puched through the second steel plate. Bouth fragments hit the gelatin block. A is the fragment of the first second steel plate an C is the fragment of the first steel plate.

Recovered bullet.

 Conclusion.

The FBI uses 2 sheets of 0.91 mm hot rolled steel to simulate the resistance of the car door from a pick-up truck. At this test we have used 2 sheets of 1 mm thick galvanized steel. This is a higher resistance than the FBI criteria. We have used in this test an 90 mm long barrel. 

The .311 FMJ-RN 71 grains bullet is a standard FMJ bullet suitable for training, target and sport shooting. The .311 FMJ-RN 71 bullet is suitable for military use but the bullet is not able to penetrate body armor. The drill performance at this test satisfies to the FBI test protocol of a required penetration depth of minimum 12 inch after defeating the car door stimulant. Like the most FMJ bullets this .311 FMJ-RN bullet has a litle bit over penetration in bare gelatin!

This is a 7.92x24 FMJ-RN 71 cartridge intend fot PDW use, but used in a pistol. A 7.92x24 FMJ-OGI-71-P for typical pistol home defense use exists to prevent overpenetration.

 7.94x24 FMJ-OGI-71- Pistol

 Link to 7.92 x 24 mm cartridge selector