My initial thoughts for this seige weapon was that it would be the best choice due to the fact of it using a bolt which is fast meaning that the momentum of the bolt would impact the barrel and make it fall over.
Some difficulties is that we have some group members away meaning that everyone wont be up with the program when it comes to the construction faze of things.
I think that the design and tech stages will be good and that we already have good idea's even before we had to find 6 siege weapons, but when we did have the 6 siege weapons we knew that the ballista would still be better due to the fact that the trebuchet in which you get the coounter weight off it wont work well. also because of the fact that we know the sort of design, so this is why we choose the ballista.
In the end i think that our ballista should be easy to move but still powerful enough to knock barrels down.