Assuming you are not focusing on ease of convincing your spouse to let you get another gun. ( pro tip: tell them that you are taking your gun to the shop to have some work done on it, but carry an empty case. Bring back the new gun in the old case, bada bing, bada boom. 
)
If you are buying retail, you go to a LGS or any shop that has a FFL. Fill out form 4473 ( don't commit perjury, they take a dim view on that, sometimes. ) and they will run a back ground check, NICS, and if it comes back clean, you have satisfied the Federal requirements. Then you have state and local laws to follow, but that's a whole 'nother kettle of fish.
From personal experience in one of the few parts of Florida worth living in...
I had ordered a lever action through Academy. From walking to the counter, to walking to the front to pay, it was maybe 20 minutes. While I was standing at the counter waiting on them to bring it from the stock room, I saw a single action revolver in the case, same caliber. I thought "Hey, why not, I may want to shoot a 'cowboy' match some day, so filled out the "paper work" (actually Ipad, it was all done electronically.) and got both done under the same background check.
Have my CCL so no 5 day wait (another reason to renew it when it come up, even though Florida changed who could legally carry concealed. ) Settled up, walked out to the truck, and was on my merry way. 
If you are buying private seller, the situation is a bit less formal than what is listed above. The code is, well, it is...
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