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DBP87 5.8x42mm: China’s High Velocity Caliber

by David Fortier   |  November 29th, 2017 0

DBP87-Feature

For the last few decades, the American 5.56x45mm and the Russian 5.45x39mm have dominated the world’s small-caliber, high-velocity (SCHV) ammunition. Surprisingly, in the mid-1990s the Chinese military introduced an indigenous 5.8x42mm SCHV assault-rifle round of its own. As with the Russians, the advantages of SCHV assault-rifle ammo observed in Vietnam War battle reports did not go unnoticed by the Chinese military. In March 1971, the Chinese military logistic department commenced a small arms research meeting known as the 713 Conference in Beijing to develop the design criteria for an SCHV cartridge. The design criteria called for a cartridge of approximately 6mm caliber, 1,000 meters-per-second muzzle velocity, with the goals of reducing recoil and ammo weight while improving accuracy and terminal ballistics over the Type 56/M43 7.62x39mm round.

The following 744 Conference narrowed down the calibers under consideration to 5.8mm and 6mm caliber. The cartridge case was to be selected from seven designs with overall cartridge lengths ranging from 56mm to 59.5mm. However, the new small-caliber cartridge development was mostly a paper project for the initial eight years. The actual initiation of the project didn’t begin until late 1978 after most of the cultural-revolution turmoil had died down. By 1979, the 5.8mm caliber and the 42mm case were chosen as the final design for the new SCHV round. The project completed its development in 1987, and the new SCHV assault-rifle cartridge was officially designated as the DBP87.

Shortly afterward, in 1988 Chinese small arms engineers started work on a long-range, heavy-load version of the 5.8mm cartridge to be used with the corresponding developments of a 5.8mm sniper rifle and 5.8mm lightweight General-Purpose Machine Gun (GPMG). The 5.8mm heavy-load variant was created as a replacement for the obsolescent Type 53/Mosin-Nagant 7.62x54R rimmed full-power cartridge. Development of the 5.8mm heavy-load cartridge was completed in 1995.

The Chinese military has since developed a variety of small arms chambered for the new cartridge. The first was the QBZ87 assault rifle, an updated Type 81 chambered for the 5.8mm, primarily used as the test bed for further 5.8mm ammo development.

Next came the QBZ95 assault-rifle family, comprising the QBZ95 assault rifle, QBB95 squad automatic rifle/light machine gun and the QBZ95B carbine. The QBZ95 (Qing, Bu-Qiang, Zi-Dong, 1995 Si, or Infantry Rifle, Automatic, Model 1995) is a modern-looking, 7½-pound (3.25 kg) assault rifle in the bullpup configuration. The QBU88 sniper rifle, also a bullpup, became available in 1997. A lightweight, belt-fed GPMG known as the QJY88 was also developed. Both the sniper and the lightweight GPMG were specifically designed for the 5.8mm heavy-load cartridge but were also backward compatible with standard 5.8mm rifle ammo. Recently, another member of the 5.8mm weapon appeared as the QBZ03 assault rifle. Instead of the bullpup layout, the QBZ03 is in the traditional configuration, with its magazine and action in front of the trigger and pistol grip like an AK or AR.

The 5.8x42mm (left) and the 7.62x39mm (right). The 5.8mm is intended to replace the 7.62mm as the standard Chinese assault-rifle caliber.

The 5.8x42mm (left) and the 7.62x39mm (right). The 5.8mm is intended to replace the 7.62mm as the standard Chinese assault-rifle caliber.

The 5.8mm standard rifle load has a 64-grain (4.15 g) FMJ bullet with a jacket made of steel and copper-washed coating. The 24mm-long projectile has a very streamlined external shape with a sharp bullet ogive and a sizeable boattail. The bullet has a composite core that consists of a pin-shaped hardened steel penetrator located near the base of the bullet, with lead as the filling material between the penetrator and the jacket, as well as the tip cavity. The steel penetrator is 16mm in length, 4mm in diameter and weighs 23 grains (1½ g).

The 5.8mm cartridge has a 42mm-long case with a one-degree taper in the body from its 10½mm (.413) base. The bottle-neck shoulder and the neck are both 4mm long. While the tapered case design helps both ammo feeding and extraction, the straight-wall case design of the 5.56mm yields better accuracy. Steel is used as the primary material for the 5.8mm case likely because of the cost. The steel case is less expensive and lighter than the brass case of the 5.56mm. However, it requires extra corrosion protection in the form of a brownish lacquer coating that causes many other problems in itself. A harder and more brittle metal, steel tends to form a less than perfect seal in the chamber and more easily develops case ruptures that could lead to a weapon malfunction. To ensure high extraction reliability, the 5.8mm case has a thick rim and a good-size extractor groove.

The 5.8mm round’s silver-color propellant in small disk-shaped pellets. Also note the projectile size difference between the 7.62mm and the 5.8mm rounds on the upper right.

The 5.8mm round’s silver-color propellant in small disk-shaped pellets. Also note the projectile size difference between the 7.62mm and the 5.8mm rounds on the upper right.

The 5.8mm cartridge uses a silvery dual-base propellant in small, dish-shaped pellets. The propellant load is approximately 28 grains (1.8 g), which is more than the 5.56’s 26 grains (1.7 g) and the 5.45’s 25 grains (1.6 g). Due to cost-cutting measures, the 5.8mm’s propellant is of the corrosive-powder variety. In contrast, NATO and other western nations have not used corrosive propellant since the end of World War II. The 5.8mm’s corrosive powder is not particularly hot either. It only generates a 41,500-psi (284 MPa) chamber pressure, which is marginally higher than that of the old single-base propellant used by the vintage M43 and much lower than the 5.56mm M855/SS109’s 55,000 psi (380 MPa). A non-reloadable Berdan primer is used.

The 5.8mm heavy load has a completely different design than that of the standard assault-rifle load. Its bullet features a slightly smaller hardened-steel penetrator at the top of the bullet. This allows the use of more lead to increase the bullet’s weight to 77 grains (5 g). The overall bullet length is lengthened to 28mm with a marginally rounder bullet ogive and a deeper boattail to improve aerodynamics in the near-subsonic velocity range. The 5.8mm heavy-load cartridge is also loaded hotter than the standard assault-rifle round. It is not advisable to use the 5.8mm heavy load in the assault rifle, except in an emergency situation. The newly available precision sniper/match heavy load uses a brass case instead of steel.

Chinese ammo designers claim the 5.8mm cartridge outperforms both the 5.56mm and 5.45mm in ballistics and penetration. The 5.8mm has more muzzle velocity and energy and a flatter trajectory with better velocity and energy retention downrange.

The 5.8mm and the 5.56mm have similar ballistic performances out to the 400-meter range. After 400 meters, the 5.8mm with its superior ballistic coefficient moves ahead. The 5.45mm cartridge and the 5.56mm fired from the short barrel of the M4 carbine are simply no match for the 5.8mm’s ballistics. The 5.8mm heavy load and the Mk262 5.56mm cartridge have roughly the same ballistic coefficiency, but the 5.8mm heavy load’s higher muzzle velocity gives it an increased velocity across the board. Both of these heavier bullets shed velocity much more slowly than their lighter assault-rifle counterparts.

DBP87-SpecsI shot the 5.8mm standard load with the QBZ95 rifle, averaging three-MOA groups at 100 meters. With a shooter more comfortable with the bullpup layout and a proper zero, 2½-MOA or better accuracy should be achievable with the same 5.8mm ammo-and-rifle combination. From my experience in the Marine Corps, the M855/SS109 5.56mm round has an average two-MOA or better accuracy when fired from the M16A2. The newer M16A4 with its heavier and higher-quality barrel is even more accurate.

The AK-74 and 7N6 5.45mm pairing can do 2½ to three MOA up to 300 meters, but the accuracy deteriorates rapidly past 300 meters. The 5.8mm heavy load fired from the QBU88 sniper rifle is claimed to be capable of 1.2-MOA grouping at 100 meters. In actual service, the QBU88’s accuracy is around 1½ to 1.6 MOA with non-match-grade regular 5.8mm heavy-load ammo. In comparison, the USMC’s new M16A4 SAM-R (Squad Advanced Marksman Rifle) can easily achieve sub-MOA accuracy when using the Mk262 5.56mm ammo. As a whole, the 5.8mm’s accuracy is a substantial improvement over the older 7.62x39mm cartridge. Furthermore, it beats out the 1970s-era 5.45mm and approaches the accuracy of the 5.56mm-and-M16A2/A4 combination.

The results of ballistic tests were published in a Chinese-language magazine. The tests demonstrated that the 5.8mm indeed outpenetrates both the 5.56mm and the 5.45mm, as Chinese engineers stated. However, the test was manipulated to make the 5.8mm look good. A long-barrel QBB95 squad automatic rifle was used instead of the QBZ95 assault rifle for the test. The 5.8mm rounds fired from the QBB95 have a 164-fps (50 m/s) advantage over the 5.56mm fired from the Fabrique Nationale FNC assault rifle. Nevertheless, the 5.8mm’s 100 percent penetration rate of the 10mm steel plate at 300 meters is very impressive.

Realistically, the penetration performance difference between the 5.56mm and the 5.8mm is much closer. Contrary to the rigged Chinese ballistic test, unbiased tests done by the USMC and U.S. Army’s Aberdeen Proving Ground show the 5.56mm M855/SS109 fired from the M16A2 rifle with the longer 20-inch (508mm) barrel has no problem penetrating the 3½mm A3 steel test plate at 700 meters. Even so, the 5.8mm is still a better AP round than the 5.56mm due to its APHC (Armor-Piercing Hard Core)-like projectile design that’s more commonly found on dedicated AP ammo. The only known AP performance data of the 5.8 heavy load is that it penetrates 16mm of mild steel at 85 meters and 3.5mm of hardened steel at 1,000 meters. The 5.8 heavy load is said to outpenetrate the old 7.62x54R at any range.

Many official and unofficial Chinese sources frequently mention how important the 5.8mm’s AP performance is. One possible explanation for the Chinese obsession with AP performance is that the 5.8mm’s AP-ammo-like core was specially designed for use against opponents who are wearing heavy body armor—such as U.S. forces.

Like most AP ammo, the test showed the 5.8mm bullet left a rather unimpressive wound cavity in the ballistic soap block. The 5.8’s wound cavity is one-third smaller than that of the 5.56’s and close to one-half smaller than the 5.45’s cavity. The thick steel jacket and the absence of a cannelure on the 5.8 bullet prevent any fragmentation. The more balanced weight distribution of the solid-lead tip with the steel core in the back also prevents the 5.8 bullet from tumbling early and erratically. Nonetheless, Chinese sources claim the 5.8 has a 60 percent increase in lethality over the 7.62x39mm it replaces.

To date, there are some known issues with the 5.8mm ammo, and most of them trace back to the use of low-cost material or poor quality control in the manufacturing process. The propellant load and bullet weight could be inconsistent depending on the production lot. The propellant fouls the gas system and the barrel with corrosive carbon residue. The primer also has a tendency to rust through after it has been in storage for a long period.

There are other special loads developed for the 5.8 caliber. The 5.8 tracer is marked with a blue-violet-color tip. The two different 5.8 training blanks are the star-crimped base blank and a frangible PVC bullet blank that feeds better and doesn’t require the use of a blank firing adapter. The non-lethal 5.8 rubber bullet is loaded with a full-size roundnose black rubber projectile in place of the FMJ.

DBP87-Velocity

A good question is: “How will the 5.8 perform in combat?” According to China’s Xinhua news agency, the 5.8 round scored its first combat kill recently in Haiti during a firefight between Chinese United Nations peace-keepers and the local rebels. The performance of the 5.8 in urban combat operations will likely be a mixed bag. On one hand, its superb penetration will be suitable for punching through tactical obstacles such as brick walls, metal doors, automobile bodies and masonry debris. On the other hand, the 5.8’s unimpressive terminal ballistics may require multiple hits to neutralize an opponent. The 5.8 will fare better in open environments like desert and mountainous terrain with its longer effective range.

The heavy-load version may look good as an extended-range small-caliber rifle round, but as the replacement for the full-caliber, high-power 7.62x54R it is a miserable failure. It is just physically impossible for the SCHV round to produce anything close to the same amount of hitting power and bullet energy as the larger 7.62 caliber. This is probably the main reason why the Chinese military is slow to adapt the 5.8 GPMG. The claim of the 5.8 heavy load outpenetrating the 7.62 is true, but misleading. The higher penetration comes solely from the 5.8mm’s hardened-steel penetrator, which the all-lead-core 7.62 lacks.

Is developing the 5.8x42mm cartridge really worth the effort? Politics and national pride probably had as much to do with its development as the Chinese military. It seems like the Chinese engineers did a decent job in designing the 5.8 cartridge. The problem is that the Chinese military went on the cheap in manufacturing it. We would only see the real potential of the 5.8 if it were to be made with the same material and high manufacturing standard, such as using a brass case, hotter and non-corrosive propellant, tighter tolerances and good quality control, as the American and European NATO rounds. As of now, whatever edge the 5.8 cartridge has over the 5.56 is not enough to make the difference in real combat. The 5.8 may excel in some areas because it has a slightly heavier bullet, a larger cartridge case and more propellant. However, the performance improvements are small; in most cases they are just 5 to 10 percent. In other areas, such as accuracy and lethality, the 5.56 is still a better round by a comfortable margin over the 5.8. Perhaps, during its early development, China’s SCHV ammo should have been built in 6mm class in the first place.

 

 

 

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