[Dominator1619]

That truly depends on how far and what goals you are aiming for. Just to give you an idea, watch the robot in 3 days video about their linear shooter. They are using a CIM geared up to roughly 8,000 RPM (if I'm remembering correctly they are gear up about 1.5:1 and a CIM standard is around 5,200 RPM). You also have to consider the pressure you are applying to a disc and how much that affects the speed of your shooter. I would suggest looking through all the legal motors that you don't plan on using for other things and see what you can find. A good place to start can be the BaneBots motors. Many of those motors have a very high RPM output and have many options to how you can apply them for your needs.