FMJ stands for full metal jacket. This type of ammo is most commonly used in military and law enforcement applications but is also popular among recreational shooters. FMJ rounds are typically more affordable than other types of ammunition, making them a great option for budget-conscious shooters.
FMJ rounds typically have a lead core surrounded by a brass or steel jacket. The jackets on FMJ rounds are very hard, which helps ensure that the bullet does not deform upon impact. This can help increase accuracy, as deformed bullets can cause flyers (erratic shots beyond the main group). Additionally, the hard jackets on FMJ rounds tend to resist fouling better than softer jacketed Rounds or lead projectiles do.
Johnny Edited answer June 29, 2022