Pen -
Going through packing.org is tedious, but most of the information you want is there, either in the state sections or in lins off of them (state FAQs, firearms laws posted by the state itself, etc.)
The short form is this - some states require a permit to purchase (Illinois). Most merely adhere to the federal background check required when you purchase any modern gun from a dealer. Black powder guns and certain older cartridge guns are considered "Curios and Relics", and have fallen out of the federal scrutiny.
Carry licenses or permits vary from state to state. Kentucky isuues a license for Concealed Carry of Deadly Weapons. They license the individual, and not the gun. Many states issue a license to carry a concealed firearm..ONLY a concealed firearm. Some states issue a PERMIT to carry a specific concealed firearm, and require that you register that gun on the permit and ONLY that gun. The legal difference between permits and licenses is a can of worms in itself. The difference between a firearms permit/license and a permit/license for concealed WEAPONS is another sticky point. Kentucky holds out receprocity to any legally issued permit/license so long as the carrier is 21 or over. Several states have refused to honor Kentucky licenses because they allow "deadly weapons". Even though my license allows this, IN Kentucky, a carrier is subject to the laws of the state he is traveling through.
The only individual firearms requiring licensing are Class III - full auto, sawed-offs, and silenced weapons. Eventhen, some states permit their sale and possession if the federal checks and taxes ($200 for each transfer of ownership) and some states forbid sale or possession.
If this has added to your confusion, take heart

It only scratches the surface.
The lingering question is, "What sort of politician or police officer would fear an HONEST man or woman with a gun?"....Sorta answers itself, don't it?