what you can see here are detachers wich have FireWeapons Input. this works by having a bomb with scale 0,0,0 and a fuselage attached to the detacher. when launching the bomb, the fuselage is launched, too. yep, ist that simple.
the blue ones hae boom25 as Input, the red ones use the boom50. the detach force is the same for both.

in order to make it easier, ive already prepared some stabilizers (you can Change the size of them, but you cant remove them.) they have almost no wheight. some of them have small wings for stabilization. just attach your projectile to the one you like and shoot it.
btw you can not attach stuff to the ones with the ball. those are already finished slug projectiles, wich have a pretty short range but much power tho

i´d like to see some other cool projectiles. feel free to put a link to your best creation in the comments