Gun Control & RKBA

State and local laws do apply, though. You would do well to check to see what applies in your specific circumstances.

Florida allows for that, I am sure California does not. And of course, "everything is illegal in Massachusetts".

https://www.flsenate.gov/Laws/Statutes/2019/0790.0655
790.0655 Purchase and delivery of firearms; mandatory waiting period; exceptions; penalties.—

(1)(a) A mandatory waiting period is imposed between the purchase and delivery of a firearm. The mandatory waiting period is 3 days, excluding weekends and legal holidays, or expires upon the completion of the records checks required under s. 790.065, whichever occurs later. “Purchase” means the transfer of money or other valuable consideration to the retailer. “Retailer” means and includes a licensed importer, licensed manufacturer, or licensed dealer engaged in the business of making firearm sales at retail or for distribution, or use, or consumption, or storage to be used or consumed in this state, as defined in s. 212.02(13).
(b) Records of firearm sales must be available for inspection by any law enforcement agency, as defined in s. 934.02, during normal business hours.

(2) The waiting period does not apply in the following circumstances:
(a) When a firearm is being purchased by a holder of a concealed weapons permit as defined in s. 790.06.
(b) To a trade-in of another firearm.
(c) To the purchase of a rifle or shotgun, upon a person’s successfully completing a minimum of a 16-hour hunter safety course and possessing a hunter safety certification card issued under s. 379.3581. A person who is exempt from the hunter safety course requirements under s. 379.3581 and holds a valid Florida hunting license is exempt from the mandatory waiting period under this section for the purchase of a rifle or shotgun.
(d) When a rifle or shotgun is being purchased by a law enforcement officer or correctional officer, as those terms are defined in s. 943.10(1), (2), (3), (6), (7), (8), or (9), or a servicemember as defined in s. 250.01.

(3) It is a felony of the third degree, punishable as provided in s. 775.082, s. 775.083, or s. 775.084:
(a) For any retailer, or any employee or agent of a retailer, to deliver a firearm before the expiration of the waiting period, subject to the exceptions provided in subsection (2).
(b) For a purchaser to obtain delivery of a firearm by fraud, false pretense, or false representation.

And, as you can see, a 3rd degree felony for the seller, and the buyer in Florida if they don't follow state law. There is no Federal/National waiting period. States, cities, well, that's a Glock of a different caliber, er, horse of a different color.