In yet another attempt to educate the masses about the AR-15, and dispel the BS being spewed by the press and many politicians, here is some information about rifles and their power.
There are pretty much two measures of the performance of a particular rifle round, speed and energy. Another measure of performance is penetration.
Speed – This is pretty self explanatory. This is the measure of how fast a bullet is when fired. Of course, based on many factors such as the shape and weight of the bullet, this speed will dramatically change for some bullets and limit their range. It is a pretty good measure, though. Typically, speed is measured in Feet Per Second (fps). Speed really isn’t important in and of itself.
Energy – This is probably a much more important measure of the performance of a round in that this is the measure of mass and speed, combined. Typically, energy is measured in Foot Pound-Force (ft-lbf).
Here is how the rounds used by the AR-15 (shown in Blue) fit when compared to typical rifle rounds. Please note that AR-15’s are typically chambered for .223 and 5.56 ammunition.
You might also note that the next lowest rifle rounds, when it comes to their energy, include the 7.62×39 round, which is used in AK-47’s, and then the 7.62×35, which is a newer round called the 300 AAC Black Out and is also used in AR-15’s, even though it is rare.
Penetration – This measurement is often used by the gun community, as well as ammunition manufacturers. It is important because we, as defensive gun users, do not want a bullet that hits a target (the evil doer, attacker, assailant, intruder – pick your term and definition) to go through the target and continue on its path to go through a wall into potential innocent people.
Penetration is usually tested by using ballistic gelatin, which is calibrated to be similar to a human body in density. Again, the main concern is that a a defensive gun user’s bullet will go completely through the attacker and into another person behind them. From the graphic below, you can see that a typical .223/5.56 round will penetrate around 14-15 inches. By comparison, most hand guns will be in the 12-14 inch range. So, yes, the AR-15 will penetrate slightly, very slightly, more than a hand gun.
Penetration is also tested by seeing how well a round goes through typical walls in a home, which are made by using dry wall boards. There are a couple of good discussions of the AR-15 as compared to hand guns HERE and HERE. What you will find from reading these tests is that the typical hand gun rounds penetrate walls far more than AR-15 rounds.
Summary – It is clear that the typical AR-15 rounds are:
more powerful than hand gun rounds when it comes to total energy
considerably less powerful that other rifle rounds, in fact, most States in the US will not allow .223/5.56 rounds to be used in hunting deer because they just are not very effective
less likely to penetrate walls than hand gun rounds
able to penetrate a slight bit more than a typical hand gun round
The AR-15 is NOT a high powered rifle. That is really the end of the discussion.