Looking to take my self-built CT "other" on the road. Is my CT legal in other states that are legal to own a AR-15? ie PA, NC, SC, GA, FL
Thanks!

Yes. It's regulated as a pistol in most other states (without a vertical grip) or as a "firearm" (with a vertical grip and what CT calls an "other").

Obviously some of the surrounding states like NY and MA will take exception to it, so keep that in mind if driving through.

To know for certain you would have to look at EACH state's specific firearm laws. Keep in mind that if the Other is defined as a pistol you may have issues depending on each state's handgun possession (and carry/transport) laws. Again you really should take the time to do a quick search of each state's firearm laws. The actual state laws not some generic summary from the NRA or the like. It could very well come down to the barrel lenght.

As always FOPA applies for transporting which means you have to be legal to possess firearms (or a handgun if the Other is a handgun) at your destination. You would not be covered in any state where you stop for thing other than food/fuel (and perhaps lodging) where the firearm is banned or regulated.