Several firearms laws are federally regulated, most in fact. Firearms do have to be registered as far as serial numbers, make, model, caliber, etc. but firearms registered to an individual are not tracked. Think of your driver's license as an example. You don't have to have a license to own a firearm, unless it's fully automatic or suppressed, which in that case you have to have a Class 3 Federal Firearms License unless you're in the military of course. You can actually buy a federal tax stamp and purchase a suppressed weapon if you're willing to pay the $200-$250 (can't remember which) license fee and wait a year and a half or so for your stamp to come in. You can track a firearm thru an exhaustive type of search but you're at the mercy of the first person who sells the firearm on a handshake to another individual. Say I buy a handgun from a gun store, that handgun purchase is entered into the store's database with my name with all my information, but, a year from then say I sell said handgun to my neighbor for $300 cash. I can legally do that and not technically have to have any paperwork. I would get a receipt if it were me but according to the laws, there is nothing illegal about an individual selling a firearm to another individual in the US. Except for handguns, of which you have to be 21 years of age to own, shotguns and rifles can be sold to 18 year olds here in the US. The only actual gun REGISTRATION in the U.S. is with guns that are suppressed (equipped with silencers), fully automatic weapons, or SBRs(short barreled rifles). These weapons all fall under the NFA(National Firearms Act) and are tracked thoroughly.
States are able to dictate some firearms laws at the state level and it varies from state to state on how restrictive these laws are. State laws usually deal with if a person can carry a concealed weapon or not, what types of establishments said weapons can be carried into, or whether to have open or concealed carry firearms laws.
If you're talking about CCL (concealed carry licenses) they vary greatly from state to state. Here in Arkansas, when you first go for your CCL, you have to take a class from a certified instructor, then qualify on a range, pay the instructor fees and the licensing fees to your respective state. The license takes about 6 months the first time to process and it looks pretty much like a driver's license (at least in Arkansas it does). The initial license will cost you around $150.00 or so. The Arkansas State Police handles all CCL licensing in my state. The CCL is good for five years and will stipulate "allowed to carry any legal handgun" on the license once you receive it. Every five years you are required to qualify on a certified firing range but you don't have to ake the course over again. The firearms course is a one time deal. Here in Arkansas, the actual shooting exam is pretty much a joke. You fire 25 rounds from soup to nuts. Five shots one handed from your strong hand, five shots one handed from your weak hand, ten shots two handed, and then a final five shots one handed from your strong hand again. You don't have to get the shots in the ten ring or anything, just put them on the paper. If I remember correctly, it costs around $65.00 for the renewal fees plus range fees for wherever you go to re-qualify(has to be a certified CCL renewal firing range).
Hope that helps. Have a good week.
Yeah, what Ghost said.
However, in Michigan at least, if I were to sell a handgun the purchaser would have to go to their local police station to get a purchase permit, unless they have have a CPL. Either way you have to bring paperwork back to the PD for them to enter the info on the pistol. I was under the assumption that was a federal law. Apparently it's a state law?