300 Blackout vs 308 Winchester

Description

Surely, we are not actually comparing the 300 Blackout to the 308 Winchester, right? While it’s true that the 308 offers a completely different performance, at least in terms of supersonic offerings, the 300 Blackout does provide some benefits in certain applications. In this article, we will be discussing these benefits, along with many of the differences between the 308 Winchester and the 300 Blackout.

Physical Attributes

Based on appearance alone, you can probably guess that the 308 Winchester and the 300 Blackout are very different cartridges with very different capabilities. In fact, the only real similarity shared by the cartridges is that they are both 30-caliber bore sizes.

Although the name may have you thinking otherwise, the 300 Blackout uses the same 0.308-inch diameter projectiles as the 308 Winchester. 0.308-inch diameter rifle bullets typically weigh somewhere between 100 grains and 250 grains, with some exceptions to this range. Although the 300 Blackout and 308 Win can both use the same projectiles, bullet weights found in factory loads are often very different between these cartridges.

From the factory, the 308 Winchester is most often loaded with bullets ranging from 147 grains to 180 grains, though there are many loads that fall outside this range. With supersonic 300 Blackout offerings, bullet weights typically fall between 110 and 150 grains, while subsonic offerings typically fall between 190 and 220 grains.

To fit these heavy 30-caliber projectiles into the length restrictions of an AR-15 style magazine, the 300 Blackout has a very short case length by design (in terms of rifle cases), measuring a mere 1.368 inches. While this may be taller than many handgun cases, it is only 67.9 percent the height of the 308’s empty case length of 2.015 inches.

Not only is the 308 Winchester much taller than the 300 Blackout, but it is also much wider. The 308 has a rim diameter of 0.473 inches, whereas the 300 Blackout has a much smaller rim diameter of 0.378 inches. This extra width and height give the 308 Winchester an H2O capacity that is over double that of the 300 Blackout.

Power

Based on the size difference of these cartridges alone, it’s not hard to imagine that the 308 Win is more powerful than the 300 Blackout. But don’t be fooled into thinking that size is the only factor that plays into the power difference, as pressure is another important factor. In fact, SAAMI lists the 308 Winchester at a maximum pressure rating of 62,000 psi, which is just about 13 percent more than the 300 Blackout’s maximum pressure rating of 55,000 psi (SAAMI).

With these differences in pressure and capacity, the 308 produces significantly more muzzle energy than the 300 Blackout. In general, factory load offerings for the 308 Winchester produce somewhere between 2,600 and 2,800 ft/lbs. of muzzle energy. Some loads, however, such as Hornady’s 150-grain SST Superformance in 308, can exceed this range, producing nearly 3,000 ft/lbs. at the muzzle. These are very impressive figures for a standard short-action cartridge.

Unfortunately, the same cannot be said for the 300 Blackout. When it comes to supersonic factory load offerings, the 300 Blackout typically produces somewhere between 1,200 and 1,400 ft/lbs. of muzzle energy. While this range is on par with many other AR-15 style cartridges, it is only about half the kinetic energy of the 308 Winchester.

So, although the 300 Blackout can be effective on medium to somewhat large game at short distances, the 308 Win is a far better choice for those who wish to hunt or shoot at longer ranges.

Subsonic

While supersonic 308 loads may be producing over double the muzzle energy of supersonic 300 Blackout loads, subsonic ammunition is a much different story. In fact, when it comes to the muzzle energy of subsonic offerings, the 308 and the 300 Blackout produce an equal amount of power (with similar loadings). But how can this be with the large difference between these two cases?

The most important factor to consider about subsonic ammunition, regardless of the cartridge, is that a maximum velocity (about 1,135 feet or less per second at sea level) exists to remain subsonic. So, although the 308 is much larger than the 300 Blackout, its extra case capacity is not useful when firing the same bullets at the same velocity.

It should be noted that most semi-automatic 300 Blackout setups are designed to cycle subsonic offerings reliably, often utilizing pistol-length gas systems. The same reliability cannot be said about most semi-automatic 308 setups, where longer gas systems (not conducive for reliably cycling subsonic ammo) are often present. For those who wish to shoot subsonic 308 Win, bolt actions make for an excellent option.

So, if your primary intention is to shoot as quietly and efficiently as possible, subsonic 300 Blackout is a hard option to beat. In fact, the 300 blackout is currently the most popular centerfire rifle cartridge in terms of subsonic offerings.

Recoil

So, if the 308 Winchester and the 300 Blackout are producing the same muzzle energy with subsonic loads, that must mean that they are producing the same recoil levels, correct? That is correct; with subsonic load offerings firing the same projectile at the same velocity, the 300 Blackout and the 308 Win produce the same amount of recoil (assuming the same weight setup).

With supersonic load offerings, however, this could not be further from the truth. Assuming that each cartridge is fired out of a 7-pound setup, let’s see what the recoil difference is between these two cartridges.

If we look at Barnes’ VOR-TX 110 grain load offering in 300 Blackout, we find that it produces approximately 5.7 ft/lbs. of felt recoil with a muzzle velocity of 2,350 feet per second. If we look at Barnes’ VOR-TX 150 grain load offering in 308 Winchester, however, we find that it produces approximately 20 ft/lbs. of felt recoil at a muzzle velocity of 2,900 feet per second.

With the supersonic loads referenced, we find that the 308 Winchester produces just over 3.5 times the recoil of the 300 Blackout. Obviously, this is a substantial difference in recoil that should be taken into consideration, especially for a new shooter who is not used to recoil.

308 Winchester or 300 Blackout?

Although they both fire 0.308-inch diameter projectiles, the 308 Winchester and the 300 Blackout are very different cartridges with very different capabilities.

The 308 Winchester is an extremely versatile cartridge, capable of producing exceptional muzzle energy for a standard short-action cartridge. Although it may not be the best long-range cartridge on the market, the 308’s relatively high muzzle velocity and energy make it a very capable medium to large game cartridge at serious distances.

If, however, you want an efficient setup that’s as quiet as possible while producing very limited recoil, the 300 Blackout is a hard option to beat. Although it may not have anywhere near the muzzle energy or long-range potential of the 308, the 300 Blackout is the most popular subsonic rifle cartridge for a reason.

So, although you are the only one who can decide whether the 300 Blackout or the 308 Winchester is right for you, hopefully, this article made your decision a little easier.

–Banana Ballistics