With all the calibers available to AR-15 80 lower builders out there, 300 Blackout is probably one of the more popular options after .223 Remington or 5.56 NATO. With professional shooters regularly demonstrating its efficacy, there has been growing interest in this caliber of ammunition. However, before you can hope to master a caliber like this on the range, you have to ensure you clearly understand its benefits and limitations. This specific caliber has great terminal ballistic data. What does that mean? It’s referred to as wound ballistics, which is an offshoot field of study of how projectiles behave when they hit and transfer its energy to a target (penetration). Based on the design of a bullet and its speed of impact, we can determine how effective it will be upon impact with a target. Since the .300 BLK is a slightly larger round it’s always going to make a bigger impact than 5.56 will in CQB, so if that’s what you’re looking for, you’ve come to the right place.