SB-160

Suryutan-Balsagi SB-160
SB-160 at the National Artillery Museum in Anchŏn
Type	Mortar
Place of origin	Menghe
Service history
Wars	Innominadan Crisis
Specifications
Weight	combat: 1,020 kg
Barrel length	3.38 m
Shell	40.5 kg mortar shell
Caliber	160 mm
Elevation	+45° to +80°
Traverse	+/-5°
Rate of fire	2-3 rounds/minute
Muzzle velocity	251 m/s
Effective firing range	9,200 m

The SB-160 (formal designation: 160밀리 수류탄 발사기 / 160밀리手榴彈發射機, Illyuglyŏng-milli Suryutan Balsagi, "160mm Mortar;" short designation: 적송포 / 赤松砲, Jŏksu-po, "Pine Tree") is a 160mm caliber heavy mortar manufactured in Menghe. It is a license-produced copy of the Letnevian M42 mortar system, with minor weight-saving modifications to the towing carriage. It is one of the heaviest operational mortar systems in Septentrion, with an impressive explosive payload but a modest range and rate of fire.

Design

Owing to the length of the barrel, especially at high elevations, and the 40-kilogram weight of the standard HE projectile, the SB-160 is not loaded from the muzzle like most other mortar systems. Instead, the barrel is designed to pivot to a horizontal angle on a secondary trunnion beneath its center of gravity, allowing the crew to push a mortar projectile into the open breech. A secondary frame beneath the barrel remains stationary throughout this process, allowing the weapon to quickly pivot for reloading and then return to its original firing solution. The rear of this secondary frame also seals the breech when the barrel is locked into place for firing.

The standard SB-160 sits on a large convex baseplate, with a twin-wheeled carriage in front. For transportation, a plug with hitch is inserted into the muzzle, allowing the wheeled carriage to be towed behind a truck or artillery tractor. Weighing in at around one metric ton, the weapon is too heavy to be moved by hand, though it can be hauled a small distance to a new firing position.

The under-barrel carriage allows a usable elevation range of +45 to +80 degrees, though the barrel itself can swing up to 0 degrees for reloading. The original FSR-designed carriage could traverse 25 degrees, but the lighter Menghean copy only traverses 5 degrees to each side; further adjustments require rotating the entire weapon around its baseplate by lifting the wheeled carriage. Shock absorbers on both the under-barrel frame and towing carriage lessen the weapon's powerful recoil.

Official Menghean sources repeat the FSR's claim that a well-trained crew can fire the SB-160 at 10 rounds per minute, but this figure seems optimistic and has never been demonstrated in exercises. A firing rate of 3-4 rounds per minute seems more reasonable.

Organization

A single towed SB-160 requires a crew of 8 men, consisting of a commander, gunner, a two loaders, and four additional ammunition handlers, who also help move the weapon into position. Properly digging the baseplate into the ground can take as long as 15-20 minutes, precluding shoot-and-scoot operations. Each battery consists of six mortars in two firing platoons (or sampojo), with three batteries in each heavy mortar battalion.

Ammunition

The SB-160 mortar employs five main ammunition types. All weigh approximately 40 kilograms and share the same rough dimensions.

• BS-160GP: original high explosive-fragmentation round
• BS-160GP1: improved high explosive round from 1999 with a more powerful explosive filling
• BS-160MJ: cluster warhead with 104x Chŏl-u dual-purpose submunition
• BS-160YL: laser-guided high-explosive warhead with high-efficiency filling

There is also a sixth prototype, consisting of a long, 76mm sub-caliber fin-stabilized "arrow" shell mounted in a special sabot. This can achieve a range of 17.8 kilometers. While this improved projectile exhibited impressive range and accuracy in testing, it was never ordered into mass production, as its size made it too long to carry in the SBCh-160 self-propelled version and its narrow diameter reduced the high-explosive filling below that of a 120mm mortar shell.

SBCh-160

SBCh-160
Three-view image of the SBCh-160 and its major variants.
Type	self-propelled mortar
Place of origin	Menghe
Service history
In service	2001-present
Used by	Menghe Polvokia
Production history
Manufacturer	Gogyŏngbuk 2nd Vehicle Plant
Produced	2000-present
Variants	SBCh-160 g.Byŏlgab
Specifications
Weight	14.4 metric tonnes
Length	7.02 m
Width	3.03 m
Height	1.95 m to top of gun shield
Crew	5
Armor	welded steel plate
Main armament	160mm SB-160 breechloading mortar
Engine	DSK-7122 6-cylinder diesel 210 kW (282 hp)
Power/weight	19.58 hp/tonne
Suspension	torsion bar
Ground clearance	35 cm
Operational range	500 km
Speed	60 km/h (road) 11 km/h (water)

The SBCh-160 (formal designation: 160밀리 수류탄 발사기 차량 / 160밀리手榴彈發射機車輛, Illyuglyŏng-milli Suryutan Balsagi Charyang, "160mm Mortar Car;" short designation: 적송포 차량 / 赤松砲車輛, Jŏksupo-charyang, "Pine Tree Car") is a self-propelled version of the SB-160 mortar. It is mounted on the low-profile version of the BSCh-6 universal carrier. The mortar is centered in the open-topped chassis, and uses the same loading method as the towed version. The crew consists of a driver, a commander, a gunner, and two loaders, who are seated facing inward in wall-mounted chairs that fold upward to allow more freedom of movement when standing.

Sixteen rounds of 160mm ammunition are carried in horizontal racks of eight on either side. Once the rear two rounds on each shelf of the rack are expended, the loader on that side turns a hand crank, cycling a chain carriage that shifts the forward rounds within reach. Both loaders stand side-by-side when handling the shell on its rack, where one sets and inserts the fuse and the other attaches the primer and propellant charges. They then lift the shell at each end and ram it into the level breech.

Maximum elevation of the SBCh-160's main armament is limited to only +70 degrees due to the trunnions' height above the floor. As on the towed version, horizontal traverse is +/-5 degrees, requiring the driver to rotate the entire hull when shifting to a new target. The weight of the ammunition and mortar assembly limit the vehicle's speed and performance, and field reports suggest that the mortar's recoil dramatically shortens the maintenance life of the torsion-bar suspension.

Most surviving examples of the SBCh-160 have been retrofitted with a folding canvas frame to shelter the open-topped interior in monsoon conditions. This must be partially rolled back for firing. A few examples were refitted with a fully enclosed steel cover offering CBRN protection and a revised 32-round ammunition rack, bearing the temporary designation modifier gwa Byŏlgab (literally "With turtle shell"). This prototype was never ordered into wide-scale production, and it appears that only two vehicles were converted.

Service

Originally, the Menghean People's Army hoped to use the SB-160 at the regimental level, as a lighter and simpler replacement for 122mm howitzers of FSR origin. Even with improved ammunition, however, the SB-160 was unable to match a howitzer's range, flexibility, and rate of fire. Regular production ended in the late 1970s.

Remaining SB-160 mortars were subsequently reorganized into independent battalions at the Corps level, and later re-grouped into Artillery Divisions. Here, they could be selectively attached to divisions or regiments in support of a breakthrough effort. During the 2000s, most surviving stocks were converted into SBCh-160 self-propelled vehicles, allowing greater mobility.

Owing to the shell's high trajectory, the SB-160 is most useful in rugged terrain, where it can more easily strike targets on the far side or descending slope of a hill or mountain. All Artillery Regiments in Corps of the 9th Army contain SBCh-160 vehicles. Combat experience during the 2014 Innominadan Crisis demonstrated that the mortar-bomb's high trajectory and large payload were also highly beneficial in urban combat, when striking targets behind mid-size buildings.

See also

• GSP-152/48
• JJP-152/27