All big box stores have a lengthy approval process.
While my state no longer requires a permit to carry a concealed weapon in public, I still get one to streamline the purchase process, plus reciprocity.
Regardless of that, big box stores still go through a much longer process based on their corporate policies.
The majority of my purchases/transfers are with one that has computerized the process so they have my info, but we all step through a process to double-check. Plus, the owner has told me he personally goes through each 4473 after regular hours that his employees process to make sure no errors are made.
The ATF keeps adding more factors into the 4473, like the non-normal gender categories, that you have to make sure you understand each question. When the ATF issues a new 4473 I always ask the employee about each new question so I clearly understand how the word-salad has changed.