The Federal Bureau of Investigation (FBI) has announced it will be giving up the .40 Smith & Wesson round and returning to handguns chambered in 9mm for service carry.

While switching rounds does not have to mean getting a new gun–springs and barrels can be replaced in many models to switch calibers–the FBI makes clear new guns will also be purchased for its “approximately 13,000 agents by 2016.”

This return to the 9mm comes 30 years after a 1986 Miami shootout in which a wounded man was able to kill two agents and hurt a third, leaving the FBI convinced the round did not penetrate deep enough to stop aggression. Of course, a lot has changed in the firearms industry over the last 30 years, not the least of which is ammunition technology.

According to The Washington Post, the FBI “continuously tests various types of ammunition” to be sure their agents are using the best and most effective rounds. As a result, a return to the 9mm began to be considered in 2007. FBI Defensive Systems Unit chief, Special Agent Ray Cook, says that while the 9mm ranked “lowest” in FBI tests around the time of the Miami shootout, the new 9mm–specifically, “the 147 grain Speer Gold Dot G2”–receives high marks where the earlier bullets were lowest–namely, penetration.

FBI tests currently show the new 9mm gives “12 to 18 inches of penetration into the human body.” Whereas, in 1986, a round fired in the shootout did not penetrate deep enough into the chest cavity to reach the suspect’s heart.

The LAPD has already returned to the 9mm and NYPD carries a 9mm hollow-point round as well. Other police departments around the country are considering reverting from the .40 back to the 9mm, and many more will do so once the FBI makes the switch.

Follow AWR Hawkins on Twitter: @AWRHawkins. Reach him directly at awrhawkins@breitbart.com.