If you want to increase the stopping power of your standard AR-15 chambered in 5.56 NATO, then converting it to fire 300 Blackout or 6.8 SPC are both excellent options. Both rifle cartridges offer improved terminal ballistics over the 5.56 and function well for home defense, hunting, and general target shooting.
In this article I will provide you with the facts about these two rifle cartridges, and help you decide which is better for your next AR-15.
What’s the Difference Between 6.8 SPC and 300 Blackout?
The most significant difference between the 6.8 SPC and the 300 AAC Blackout is that the 6.8 SPC is designed for longer ranges, while the 300 Blackout is optimized for close-quarters combat. A backcountry hunter should pick the 6.8 SPC for longer distances, and a hunter in thick brush should choose the 300 Blackout for shorter distances.
Cartridge Specs
| 6.8 SPC | 300 Blackout | |
|---|---|---|
| Parent Case | 30 Remington | 221 Fireball/223 Remington |
| Bullet Diameter | 0.277" | 0.309" |
| Neck Diameter | 0.306" | 0.332" |
| Base Diameter | 0.422" | 0.3759" |
| Case Length | 1.687" | 1.368" |
| Overall Length | 2.26" | 2.26" |
| Case Capacity | 34.8–36.9 grains H2O | 25.1 grains H2O |
| Max Pressure (SAAMI) | 55,000 psi | 55,000 psi |
Which Is Better for Hunting?
Both the 300 Blackout and 6.8 SPC are exceptional hunting rounds, even if they aren’t designed for that purpose. However, the 6.8 SPC gives hunters an edge with its longer effective range for medium game such as whitetail deer or feral hogs: 250-300 yards, as opposed to 150 yards for the 300 Blackout.
The 300 Blackout offers shooters a low-recoil option that works well for varmints like groundhogs and coyotes. The 6.8 SPC can also do the same job, but at the cost of higher accompanying recoil.
| 300 Blackout | 6.8 SPC | |
|---|---|---|
| Effective Hunting Range | ~150 yards | ~300 yards |
| Best For | Close range hunting, hogs, deer | Longer ranges, deer, elk, hogs |
| Ballistic Performance | Comparable to thumper rounds such as 450 Bushmaster, 458 SOCOM, and 50 Beowulf | Superior energy retention, making it effective for ethical harvest at 250–300 yards |
| Recoil | Lower recoil: 6 ft-lbs average recoil | Higher recoil: 9 ft-lbs of free recoil |
Continue reading 6.8 SPC vs. 300 AAC Blackout: Powering Up the AR Platform on Ammo.com!