No canto, that's wrong.
To make projectiles just make the model and export it as projectile.dts then in the projectile shape file in the script, put the name there.
mountPoint- Where blocklander holds gun.
muzzlePoint- Where projectile comes out.
ejectPoint- Where the shell comes out.
Dont forget to always capitalize the P in Point and not the first letter.
I bolded what you asked for in post. Others are just for reference.