The firing trials were carried out together with the Swedish Defence Materiel Administration (FMV). An extremely comprehensive trial was performed in a relatively short time, while saving resources. On the one hand, this was due to the local conditions on the shooting range and on the other thanks to the close cooperation between armasuisse Science and Technology and FMV. Apart from determining the ballistic parameters, the experimental setup planned in advance with the utmost precision enabled further important results to be determined – both with regard to the function of the ammunition as well as to the burst pressure load on the crew.
Since the decommissioning of the 12 cm self-propelled Mortar 64/91 in 2009 due to its age, the combat units of the Swiss Armed Forces have not had a system for ensuring indirect fire support at short range. This capability is to be regained with the 12 cm Mortar 16. Various types of ammunition have to be tested as part of the procurement project. The 12 cm Mortar 16 system has a Ballistic On Board Computer (BOC), which calculates the required firing data such as azimuth and elevation. So that the system is able to calculate this data, the ballistic key figures of the ammunition used must be known and mapped in a ballistic model.
As part of the 12 cm Mortar 16 procurement project, existing ammunition is being subjected to a retrofit programme based on age. Specifically, this means that the existing ammunition is being modernised and retrofitted, so that it can meet the new system requirements. Five different types of ammunition will thus be available for operations and training.
From 14 to 31 August, armasuisse S+T ballistically tested four of these ammunition types at the shooting range Älvdalen in cooperation with the Swedish Defence Materiel Administration (FMV). In order to create an accurate ballistic model, each ammunition type must be fired and measured over all charges (1-8) and at three different elevations per charge. During the trial, an impressive 1227 shots were thus fired.

External ballistics
The tracking radar plays a key role here in determining the ballistic parameters. This system is used to determine the drag coefficient (an important ballistic parameter) along the trajectory of a projectile. In addition, the entire trajectory can be measured in X,Y,Z coordinates and the impact coordinate determined. For further processing, additional information on the initial velocity at launch and the prevailing meteorological conditions in the various layers of air is required. For this purpose, radio soundings with weather balloons were carried out every two hours continuously during the trial.
Function of ammunition
In addition to the external ballistic characteristics, the general function of the ammunition with regard to effect and safety also plays an important role. The experimental equipment was set up in advance such that as many findings as possible in various different disciplines were obtained. It was thus possible to examine the function of the various ammunition types during the fire.

Burst pressure measurements
During shooting, the crew in the vehicle is sometimes exposed to high noise emissions due to the firing blast. During the trial, the burst pressure load on the ear was measured at all positions of the gun crew. Based on the high number of shots, well-founded measurement results were obtained. These will allow armasuisse S+T to compile an in-depth analysis to define the maximum permitted number of shots per day for each crew member.

All measurement results obtained will now be evaluated by armasuisse S+T. Furthermore, the results for each type of ammunition will be processed into a ballistic model and implemented in the ballistics on-board computer of the mortar system. This will enable armasuisse S+T to make a key contribution to the efficient and precise use of this new weapons system. Thanks to the firing tests in Sweden, an important milestone has been reached in the procurement project. Next, the measurement data obtained will now be evaluated in detail and a ballistic model for implementation in the BOC will be created. With its introduction to the troops, a modern weapons system with accurate ballistics will thus be available for tactical operations and exercises.