ABOVE: The HS-404 turret in detail on a M1151. The idea has similarities with the Taiwanese T75 gun mount on a Humvee. The T75 gun is belt fed and uses powered sights, and possibly IR and thermal models. The Salvadorian mount has only iron sights. The HS-404 is ring-mounted, providing for 360 degrees arc-of-fire. The standard GPK (Gunners Protection Kit) has been modified, but remains as a manual-traversing unit.
During the 12 long years of brutal and bloody internal conflict in the 1980s, military correspondents mentioned the Salvadorian Maestranza countless times. Among others, the Armed Forces National Workshop built over 130 guntrucks and IFVs in the 70-80s, using Jupiter (7 ton), Man 630 (5 ton), Unimog (2 ton), GM/Ford (5 ton) trucks, F-250 and Dodge M37B pickups, as well as 23 tracked Woodmaster tractors. It also tackled the conversion of elderly Madsen LMGs to 7.62mm caliber, many other small arms transformations, and became notorious for performing conversions and modifications on many weapons to be used in combat. In fact, Salvadorian officers insist that they were the first ones to match an M203 to an “M16A2” (a carbine local designation is today’s M4). The prototype is said to have been presented to a USSF officer, who in turn passed the idea to Colt.
In early 2013, the Salvadorian Armed Forces Quartermaster Command (CALFA) celebrated its 100 anniversary. This military branch was established on February 26, 1913, under the name of Army National Workshop (Maestranza) by then War Minister, General Jose Maria Peralta Lagos. Today the CALFA comprises the following “battalions:” Logistical Support, Quartermaster, Advanced No. 1, and Military Industries. Within this organization, the Technological Research and Development Center (CIDET) was established (around 2007) with the sole purpose of recovering and experimenting with various weapons in store, resulting, among others, in the recycling of the HS-404 from obsolete Ouragan jet fighters and rework on M60Ds. At one point in 2008, it was planned to upgrade the M79 grenade launchers to South-African Milkor M79 standards. The M79 Milkor modification consists of fitting a pistol grip while the wooden stock is replaced by an inverted R4/R5 (Galil or FAL) folding stock. The ladder sight is removed, and an Armson OEG sight is added. The design was found feasible by Maestranza personnel, and with almost 2,000 of these weapons in inventory, the idea became appealing for a short time. Unfortunately, the project was dropped when the colonel who promoted the project was reassigned. It is hoped that the CIDET engineers might reconsider the idea.
Under the leadership of a young captain, graduated from the Taiwanese Military Academy, the CIDET has transformed the shape of several military outfits with his ideas. Among others, he has followed the steps of (now retired) Colonel Oswaldo Marenco, the designer and builder of most of the Salvadorian guntrucks, designing and building the next generation of guntrucks/armored vehicles. The VCTA2, a “tank hunter” vehicle, has its origins in the 2007 “M” Project, which in turn started around 2004-2005 within Maestranza/Estranfa. The prototype was based on a Ford 5 ton truck, and those photographs that we were allowed to review in 2005 showed a 4×4 truck with a redesigned cabin much to the HMETT style. In the bed there was an armored rotating “tub” where a twin 20mm gun rested. It has been indicated that the original gun system was actually an M55A2 AAA mount, but this was later changed to a new mount, of original design, holding the two HS404 recycled from the Ouragan jet fighters. A couple of years into the project, the testing was suspended after an internal audit found irregularities, and some $25,000 missing from the funds allocated to the prototype. After this setback, the CIDET was established around 2007 and work on the “new” armored model started as the M Project. The original prototype was stripped, and the “tub” became a fixed item supporting a rotating open-topped turret. It became known as the Lizard due to its shape, but received the official designation of BCTA1, or armored tank-hunter model 1; this was later changed to VCTA1, or tank-hunter vehicle model 1. The armored body rested on a 5 ton Ford truck chassis, and four other Ford chassis had been obtained to complete the Project. Once all the systems had been tested and proved, the go ahead was given to transform the four additional Ford truck chassis, with upgraded 175hp diesel engines, with a redesigned armored body and a newly designed electrically driven turret, and using many of the principles, components and tools of the VCTA1. It was indicated in mid-2012 that the VCTA2 was based on the Dodge RAM pickup truck chassis, but by early 2013 it was becoming clear that the first two VCTA2 were built using the already mentioned Ford chassis; two more VCTA2 were ready by May 2013. Hopefully, enough vehicles can be manufactured to form a tank-hunter/fire support squadron, in addition to a troop transport variant to equip a second squadron for mechanized infantry.
Recycling HS404 Guns
El Salvador received 18 Ouragans, each equipped with four HS404 cannons, so there would be a total of at least 72 weapons in store, with several more spares. In 1981, the guerrillas blew up 8 Ouragans, but even assuming that all 32 cannons went up in smoke with the planes, there still would be 40 of them (and certainly more, adding the spares) in the remaining planes and storage. This author forwarded the idea to recycle the cannons to ground mounts in the early 1990s; the idea was finally accepted some 10 years later. The first experiments to recycle the HS404 took place on Cashuat APCs modified accordingly. Although the laboratory was satisfactory, the cannon rate of fire was found to be problematic. Another problem was the lack of appropriate sights to maximize the range.
The CIDET took over the idea, first attempting to use the guns as antiaircraft artillery. Approximately 12 mounts were designed and built, although only one has been photographed. Certainly the AAA system used the electrical mechanism later used in the turret to be mounted on the VCTA1, and later the VCTA2. According to CIDET officers, it was discovered that the AP round available to the Armed Forces for the guns actually reduced the rate of fire of the cannon and had the ability to penetrate most of the armored vehicles found in the region.
The turret found on the VCTA2 received two HS404s, and it came with a 2-speed transmission, as does the AAA variant, to facilitate target tracking. Assuming that the turret has been inspired on the TCM-20 system, it should be able to rotate 360º in 5.2 seconds, and to move in an arch from –10º depression to a +90º elevation in 60º per second. The HS404 has an effective range of 1,200 m against aerial targets, 1,500 m against ground targets, and a maximum range of 4,000 m. Two HS404s provide for a rate of fire of 1,300 rpm. Each cannon weighs 45 kg, and has a full-length of 1.4 m, and a barrel length of 2.06 m. A 60-round drum magazine feeds each cannon. The turret of one of the M1151 was also modified to accept a HS-404 in place of the M2HB. The ring was worked to accept the weight of the loaded gun and reinforced to withstand the recoil of automatic fire. The mounts have iron sights only. The side and front shields and support equipment were equally modified, and four spare magazine drums are now hung on each side. It is reported that four M1151s have been modified in this manner.