Former New Jersey Superior Court Judge Andrew Napolitano once said, “the Second Amendment is an extension of the natural right of self-defense that protects the right to shoot tyrants, and it protects the right to shoot at them effectively, with the same instruments they would use upon us.”
In other words, a weapon such as an AR-15 is the preferred weapon of law-abiding citizens because it effectively confronts violent threats from tyrants, oppressors, and most often, everyday criminals.
Recently, you may have heard about a Florida woman who was eight-months pregnant and saved her husband and teen daughter from a pair of violent intruders who’d broken into the family’s home. Jeremy K. was at his home 25 miles southeast of Tampa, when around 9pm, two armed men broke inside.
According to Jeremy, “As soon as they had got the back door opened, they had a pistol on me and was grabbing my daughter. I’m telling them, ‘I have nothing for you,’ and they’re like, ‘Give me everything you got.’ It became real violent, real fast.”
Jeremy told police one of the burglars pistol-whipped him and another kicked him in the head, causing enough noise to attract the attention of his wife, who walked into the room to see what was going on and soon found herself running from bullets.
Jeremy’s wife ran back into a bedroom located on the back side of the house and grabbed an AR-15. Then, she waited until one of the intruders came looking for her and she fired one round striking the bad guy.
The intruder ran from the home and was found dead in a ditch roughly 200 feet from the home. The other intruder fled and was not located by authorities.
Jeremy told local media, “Them guys came in with two normal pistols and my AR stopped it. My wife evened the playing field and kept them from killing me.” Clearly, this guy married the right woman.
Now, there are a lot of reasons people love their AR-15 rifles. But, one specific reason people choose an AR-15 for home defense is because AR-15s inflict much more damage than most pistols, meaning they are better at stopping a threat.
This is largely because of the speed at which bullets leave the AR-15… they are much faster out of the muzzle of an AR-15 and deliver a more devastating blow, compared to bullets from a handgun.
With that being said, anyone who owns an AR-15 knows there are a lot of different options when it comes to ammo, however, choosing the right bullet is key to achieving the maximum effectiveness of your AR.
Considering this, I want to share with you two important factors when choosing ammo for your AR-15.
Barrel Twist Rate. Twist rate is the ratio of inches the bullet travels down the barrel to rotate the projectile one full turn. For example, a 1-7 barrel twist rate means that the rifling will spin the bullet one revolution in 7 inches.
When it comes to choosing ammo, understanding the twist rate is important for picking the right bullet.
Most modern AR-15 barrels come in three twist rates: 1:9, 1:8, and 1:7. The 1:9 barrel is best for stabilizing lighter and mid-weight bullets. The 1:8 twist barrel is the most common and versatile of these three and provides flexibility for shooters to use multiple weights of ammo.
Lastly, the 1:7 twist barrel is the “mil-spec” choice, as the U.S. military adopted this setup in the 1980s. The 1:7 barrel can stabilize up to a 90-grain bullet, however, there is a drop in performance when shooting lighter ammo through 1:7 barrels.
Grain. Bullets come in different weights referred to in “grains,” such as 55-grain, 62-grain, 77-grain, etc. The thing is, bullets of varying weights require different amounts of spin to stabilize it in flight.
Basically, with an AR-15, it’s important to find the right balance of spin (twist rate) for the bullet you’re shooting.
The problem is, if a bullet spins too slowly, it won’t stabilize enough to achieve ideal velocity and will be less accurate. On the other hand, if a bullet is over-stabilized, it could actually fragment in flight and come apart.
As a general starting point, the 1:9 barrel is best for lighter and mid-weight bullets between 45 and 77 grains. The 1:8 twist barrel is ideal for rounds up to an 80-grain weight. The 1:7 twist barrel can handle up to a 90-grain bullet.
By no means are the twist rate and grain of the bullet the only factors to consider when picking your ammo. There are numerous other variables to consider including barrel length and environmental considerations that affect ballistic performance.
However, with the information above, you can pick the ammo that will hopefully give you the best accuracy with your specific AR-15 barrel. And, luckily for you and me, there are plenty of good ammo makers to choose from these days, such as Hornady.