A while back, my purchase of a handgun under a state "instant check" system took 5 WEEKS FROM BEGINNING TO END. I had held a state issued carry permnit for about 11 years, at the time.
Renewal of my permit, last summer, also required the "instant check" routine, which took place in about 5 minutes or less, not counting the time spend filling out a form.
A few months ago, re the purchase of another handgun, the "instant check" took a couple of minutes. GO FIGURE. Perhaps, as with the manufacture of automobiles, where one is advised to avoid "monday cars", insta checks are better done some days, than others. Once again, GO FIGURE.