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 Remington Special Purpose Cartridge (SPC) and 300 AAC Blackout is this: the 6.8 SPC is designed to deliver better terminal ballistics than the 5.56 over farther distances, whereas the 300 Blackout is designed for close-quarters combat – as well as make practical supersonic and subsonic cartridges both available to shooters.
Cartridge Specs
When evaluating two cartridges, it’s good to begin by analyzing their physical specifications.
The most striking difference between these two cartridges are the calibers of the bullets either fires. The 300 AAC Blackout launches America’s iconic .30 caliber bullet –0.309" diameter, which is almost identical to the 308 Win – whereas the 6.8 SPC fires a 0.277" diameter bullet just like the 270 Winchester.
A 300 Blackout AR-15 uses the same bolt as one chambered for 5.56 NATO, while the 6.8 SPC requires a new bolt for caliber conversion. Both rounds require a barrel change, but in terms of ease of conversion, the 300 Blackout requires fewer specialized parts.
Recoil
If you’re thinking the 6.8 SPC has more free recoil due to its higher case capacity, then you’re correct. Recoil is an important consideration when purchasing a new rifle, as a round with heavy recoil will be more challenging to control and slow your rate of accurate follow-up shots.
Recoil is determined by muzzle velocity (measured in feet per second, or fps), propellant charge weight, bullet weight, and rifle weight.
On average, the 6.8 SPC has around 9 ft-lbs of free recoil; 50% higher than the 300 Blackout’s 6 ft-lbs average recoil.
Despite that apparent disparity, most shooters would categorize both rounds as being very soft-shooting.
However, if you’re recoil-sensitive or are training a new shooter, the 300 Blackout is the better choice.
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.
Although the 6.8 SPC offers several ballistic advantages over the 300 Blackout, the latter should not be dismissed as a hunting cartridge – especially if you hunt in heavily wooded areas. The 300 Blackout has no problem dropping a whitetail or hog within 150 yards (with proper shot placement, of course). The 300 Blackout’s ballistic performance is comparable to that of heavier thumper rounds such as 450 Bushmaster, 458 SOCOM, and 50 Beowulf, although it has considerably lower recoil.
But if you plan on taking a longer-range shot upwards of 250 to 300 yards, then the 6.8 SPC is clearly the better choice. It has the energy to ethically harvest deer at those ranges.
The 300 Blackout offers shooters a low-recoil option that works well for varmints like groundhogs, raccoons, and coyotes. The 6.8 SPC can also do the same job, but at the cost of higher accompanying recoil.
Which Is Better for Deer Hunting?
For deer hunting, both rounds can get the job done with proper bullet selection. Since the 300 Blackout can fire the same .30 caliber projectile as other popular hunting cartridges such as 308 Winchester, 300 Win Mag, and 30-06 Springfield, there are a lot of available options when it comes to hunting cartridges.
The 6.8mm bullet (0.277" caliber) is not new to deer hunting. The 270 Winchester is an extremely popular cartridge for taking whitetail, which makes suitable deer hunting bullets readily available to manufacturers and handloaders who load 6.8 SPC.
Determining which cartridge is better for deer hunting really depends on the area where you hunt and the range at which you expect to shoot a deer. If you hunt in a densely forested area (like I do in the Midwest), then a 300 BLK’s 150-yard effective range should prove more than sufficient with a. However, if you plan on taking longer shots between 150 and 250 yards, then the 6.8 SPC is the better choice.
Continue reading 6.8 SPC vs. 300 Blackout: Powering Up the AR Platform on Ammo.com