The great thing about long guns is that there's no waiting period whatsoever.
While there may be no federal waiting period for long guns, your state may have one.
If I'm not mistaken, California's waiting period is five days for long guns and ten for handguns. (I could be wrong on this; I haven't made a purchase lately.)
In the PRK, it's a 10 day wait for all firearms, plus we have to take a test or watch a video and receive a certificate before the weapon will be released to the buyer.