## 4 Results  
The study leads to four major findings, i.e., a design layout for the LGG, a novel sabot-stopping system, a structural FEA revealing deflection of the sabot stand under a specified force, and the development of a FEM for the rubber cylinder component.  
Regarding the first point, the design layout for the single-stage LGG at MCAST is presented, with a chosen configuration featuring a 3 m pump tube and launch package of 40 g, able to reach a maximum velocity of \(\approx\)500 m/s. This approach was selected to have a complementary operative range with other facilities hosting a two-stage LGG, similar to  
Figure 11: Rubber cylinder—Meshed FEM.  
Figure 10: Rubber cylinder—FEM with boundary conditions.  
the LGG at the CISAS of the University of Padova, which is able to shoot at higher speeds but with smaller projectile masses.  
A novel sabot-stopping system is also introduced. It is unique from standard LGG systems that absorb a sabot which breaks apart into multiple sections. Instead, the proposed system allows for a novel design that can absorb and dissipate the energy of a solid sabot that can be machined from a single cylinder and thus, allows for multiple shots using the same sabot-stopping setup, reducing cost and test set-up time.  
A structural FEA of the sabot-stopping system stand, the structure that mounts the system to the concrete ground, was carried out. It was found that the sabot stand has a maximum deflection of 7 mm when hit with a \(1\times 10^{7}\) N force.  
A FEM was developed for one of the energy damping components of the system, the rubber cylinder.  
The FEM was used to estimate the maximum von Mises stress predicted for the rubber cylinder, which was found to be 2.46 MPa (Figure 12). This value is lower than the typical yield strength for rubber (10 MPa) and is within acceptable limits. It is important to note, however, that the stress distribution is not uniform across the rubber cylinder. In fact, the maximum stress occurs at the inner hole on the opposite face to the impact. This could potentially cause an issue if the projectile clearance with the impactor is less than 2 mm, as the maximum displacement predicted (1.96 mm) occurs at the inner hole (Figure 13). This results in a conical decrease of the diameter, which could lead to a collision or interference of the projectile with the sabot-stopping system. To illustrate this issue, Figure 14 has been included, which shows the potential for collision or interference. If such an event were to occur, it could cause the failure of the region in the impactor tube, which could result in contamination of the projectile and/or the target. It is therefore important to carefully consider the displacement relating to the reduction of the length of the impactor tube, which amounted to 0.8 mm.  
The study focused on analysing the von Mises stress distribution resulting from a single impact between the sabot and the rubber stopper. However, it is important to note that the study, at this stage, did not include an evaluation of fatigue (i.e., performance requirements for the required number of tests), damage tolerance, or fail-safe considerations, all of which are crucial for design and safety purposes.  
Figure 12: Resultant von Mises stress.