The experimental M-8-16 launcher developed by NII-3 was brought to trials. The launcher is designed to cooperate with infantry and has the following design:
A one-axle trailer has 8 two meter long paired rails for M-8 rockets. The launcher has a horizon calibration mechanism composed of two elevation screws with pads. Vertical and horizontal aiming is achieved with elevation and traverse mechanisms. The launcher uses M-5 sights. The pyrotechnic trigger is of the new simplified type. The pyrotechnic charges are ignited with the stock trigger mechanism and battery, mounted on the launcher.
The experimental M-8-16 launcher weighs about 400 kilograms and is transported (according to NII-3 design) as a trailer behind a 1.5-ton truck with a full ammunition load and 5 more loads in the truck (80 rockets).
One volley consists of 16 rockets. The maximum range is 5300 meters. Angles of elevation: minimum 5 degrees, maximum 50 degrees. Horizontal traverse: +/- 5 degrees.
The M-8-16 launcher is designed mainly for rockets that use fast-burning (pyrocotton) gunpowder. Until these rockets enter mass production, the launcher can use standard M-8-16 rockets.
2. Purpose of trials
The purpose is to check the suitability of accepting the M-8-16 launcher into service in the Red Army.
3. Plan and methodology
- Plan: The trials will be conducted according to the trials plan, approved by the deputy chief of the Main Directorate of Mortar Armament, Military Engineer 1st Class Kuznetsov. According to the program, the following goals were made:
- Check the robustness of individual components during transport and firing.
- Check off-road performance of the launcher on various roads.
- Establish the time required to move from transport position to firing position and back. Check the convenience and speed of aiming horizontally and vertically. Establish the crew size necessary to service the launcher.
- Determine the safety of the crew during firing and the locations that they must be in.
- Check the stability of the launcher after firing (movement as a result of firing).
- Find design and production defects and determine how to correct them.
- Trials are conducted in battle conditions in the region of the 222nd Infantry Division in the region around Tashirovo.
- The robustness of the launcher and off-road performance was established on the way to positions and during firing.
- The number of required crewmen, time from travel to firing positions, convenience and speed of firing, safety and crew placement, stability when firing, and design defects were determined during training exercises and combat. In total, M-8-16 launchers fired 4 volleys at the enemy in the village of Tashirovo and in the ravine north-west of Tashirovo.
- November 6th, 1941: The launcher was towed to the firing position on a highway by a 1.5 ton truck. The range was 4400 meters. The launcher fired 3 volleys are various targets. Before the volleys, 1-2 shots were fired to sight in.
- November 7th, 1941: The launcher was towed by three horses, attached to a 45 mm gun limber. The range was 3700 meters. One volley was fired at enemy positions. Before the volley, 2 shots were fired to sight in.
Fire correction and observation was done from an observation point 200-400 meters away from the target.
- Trials and reviews from commanders confirm the necessity of creating M-8-16 mortar units and including them into infantry regiments.
- The experimental M-8-16 launcher mostly meets requirements, but has a number of design and production defects:
- The suspension is inadequate (the wheels are too small), which limits off-road performance.
- The design of the trails is unsatisfactory, which makes it difficult to move the system from travel position to firing position, especially calibrating the horizon.
- The sight mount is attached incorrectly, making it necessary to use a quadrant to aim vertically instead of the sight. It is not possible to aim at the most frequently used angles (the guides get in the way).
- The turning and elevation mechanism handles are too far away from each other and not brought out far enough, which makes aiming inconvenient and requires help from another crew member.
- There is no equipment to move and turn the launcher by hand (instructions, handles, straps).
- The launcher can be transported both by a 1.5 ton truck and horses. The off-road performance when towed by a truck is limited only by the off-road performance of the truck. When towing with horses, a pair of artillery horses with a standard artillery rig.
- 5 men are enough to service the launcher (commander, gunner, 3 loaders). The launcher can fire from a trench. While firing, the crew can stay 8-10 meters away to either side, either in cover or out.
- The rockets disperse 200-400 meters away from the target as observed by forward observers, more than standard M-8 launchers.
Mostly, when firing at 4400 meters at live targets, the rounds deviated 150-200 meters lengthwise and 200-250 meters widthwise.
The movement of the system after firing is negligible, despite the poorly designed trails.
- Trials of the M-8-16 launcher in combat showed many positive points. The launcher is light, maneuverable, can be transported by horse, performs well on bad roads and off-road when escorted by infantry, can fire at targets inaccessible by regular M-8 launchers.
- Tactically, it is reasonable to use M-8-16 launchers in batteries of 4, integrating them into an infantry regiment.
- The following changes should be made to the design:
- Replace the suspension with one similar to the 45 mm gun, or just copy that entirely.
- Add handles and straps to make turning and pushing the launcher by hand more convenient.
- Design a crate similar to the 45 mm gun ammunition crate to store one volley worth of rockets (16 rockets).
- Design skis that can be attached to the launcher in the winter.
- Change the horizontal calibration mechanism such that the launcher is supported by 4 retractable trails that can be quickly moved from travel position to firing position and back.
- Reduce the weight to 250-300 kg without compromising the robustness of parts, with the requirement that a pair of artillery horses should be able to tow the launcher and limber.
- Reduce the height of the launcher by 15-20 cm without reducing the clearance.
- Make the following changes to the elevation and traverse mechanisms:
- Replace elevation and traverse mechanism handles with flywheels.
- Move the flywheels further out.
- Their placement should be such that aiming can be done by one person.
- The carrier and sight placement should allow for zeroing of the launchers. Have a removable aligner that can be attached to the guides.
- In order to simplify service and get rid of problems associated with charging batteries in infantry units it is desirable to have mechanical pyrotechnic charges.