Artillery shells - EMP & Incendiary - how do I make them?

[nuschler22]

I have a machining table that only allows me to make regular shells. 

Is it a research I need?  A different table?

Thanks for the help.

[Goldenpotatoes]

Shells don't matter, its the type of mortar you make. There's an EMP and Incendiary variant that you can construct after doing the 'Mortars' research.

[nuschler22]

Shells don't matter, its the type of mortar you make. There's an EMP and Incendiary variant that you can construct after doing the 'Mortars' research.

Hmmmm....I have three mortars set up (regular, EMP and Incendiary) all next to each other.  I can man and fire the regular, but when I try to man the EMP and Incendiary it tells me I don't have the correct type of shell.

Edit: Just tested it again and it didn't give me that message.  Weird.