300 Blackout vs 308 – 2022 Comparison

The .308 Winchester is to a 7.62 NATO what a .223 Remington is to a 5.56 NATO. The .308 Win has been around for about seven decades and is a fairly versatile and unchallenged civilian and military round. Then came the .300 Blk, a round that was intended to easily convert an M4/M16 into a .30 caliber rifle for the special forces. Although it didn’t make it into the U.S Military, it still had a great impact on the civilian market. 

Both these cartridges use the same .308 caliber bullet, but is one really better than the other? Find an absolute answer to this question in this definitive guide comparing .300 Blackout and .308 Winchester. 

300 Blackout vs 308

Check out a quick side-by-side comparison of the pros and cons of these two rounds. 

300 Blackout Overview

The .300 AAC Blackout a.k.a the .300 Blk or just .300 Blackout is a rimless, bottlenecked, intermediate centerfire rifle cartridge that fires a 0.308-inch diameter bullet. The round was developed in 2009 by Advanced Armament Corporation (AAC) of the United States and got approved by SAAMI in 2011. 

This round was developed to increase the power of the existing 5.56 rifles by utilizing a .308 diameter bullet. In other words, the round was required to deliver the power of an AK-47 (7.62×39 mm) round inside an M4 rifle without any bolt or mag modifications. 

The .300 blk uses a .223 Remington parent case which allows it to be held inside regular 5.56 mags without any compromise on capacity. This is the only alternate cartridge for the 5.56 that can do that. Rounds like the 6.8 SPC and .458 SOCOM work with 5.56 mags but at a lower capacity.  Switching these calibers on an AR platform rifle only requires the swapping of the barrel. This round is also popular for its easy integration with SBR and suppressors. 

Designed with an intention to be accepted by the military, the .300 blk was only adopted by the Netherlands and U.K armies in a very minuscule capacity. However, the round proved really successful on the U.S market as a self-defense cartridge. More on that in the later sections. 

308 Overview

The venerable .308 Winchester has long been the exemplar for a balanced high power cartridge that can be used with semi-auto rifles and carries substantial amounts of power. It is a rimless, bottlenecked cartridge that fires a .308 inch diameter bullet and uses a .300 Savage parent case (which can be traced back to the .30-06 Springfield). 

Rather than going in too much technical detail about the history of this cartridge, I’ll put it in a simple way. The .308 Winchester is the civilian version of the 7.62×51 mm NATO cartridge loaded at a slightly higher pressure. 

Both these cartridges can be used interchangeably in rifles (that’s what SAAMI says), however, that has been a matter of debate for long.

While the 7.62 NATO is one of the most used and popular military cartridges around the world. Similarly, the .308 Winchester is also among the top five most popular hunting cartridges in the United States and possibly the rest of the world. 

The major reason for the popularity of the .308 Win as a hunting round against other popular .30 caliber rounds was its short-action design. This eliminated the need for heavy rifles and allowed the round to be used in semi-auto rifles, hence further expanding its applications. 

300 Blackout vs 308: Cartridge Specs

Check out this table for a quick side-by-side comparison of the cartridges.

	300 Blackout	308
Bullet Diameter	0.308 in (7.8 mm)	0.308 in (7.8 mm)
Neck Diameter	0.334 in (8.5 mm)	0.3433 in (8.72 mm)
Base Diameter	0.376 in (9.6 mm)	0.4709 in (11.96 mm)
Case Length	1.368 in (34.7 mm)	2.015 in (51.2 mm)
Overall Length	2.26 in (57 mm)	2.800 in (71.1 mm)
Case Capacity	21 grains	56 grains
Max Pressure (SAAMI)	55,000 psi	62,000 psi
Typical Casing Material	Brass	Brass
Typical Bullet Weight (gr)	110-150 grains	150-180 grains

300 Blackout vs 308: Ballistics

300 Blackout vs 308: Trajectory

Take a quick peek at the trajectory characteristics of different bullets fired from these two cartridges. The trajectory is affected by factors like gravity, weight, velocity, and several other characteristics. Additionally, the ballistic coefficient is the measure of how good a bullet can handle wind. The higher the BC, the more resilient a bullet is to wind. 

300 Blackout

16” barrel/BC 0.290/110 gr Hornady V-Max	9” barrel/BC 0.251/120 gr Copper HP	16” barrel/BC 0.406/150 gr FMJ Boat-Tail
100 yds: 0 “ Drop	100 yds: 0 “ Drop	100 yds: 0 “ Drop
200 yds: 6.5 “ Drop	200 yds: 9.4 “ Drop	200 yds: 10.3 “ Drop
300 yds: 23.4 “ Drop	300 yds: 33.7 “ Drop	300 yds: 34.7 “ Drop
400 yds: 54 “ Drop	400 yds: 78.6 “ Drop	400 yds: 76.9 “ Drop
500 yds: 102.7 “ Drop	500 yds: 150.6 “ Drop	500 yds: 140.2 “ Drop

308

24”barrel/BC 0.408/150 gr FMJ Boat-tail	24”barrel/BC 0.489/168 gr Berger Hybrid	24”barrel/BC 0.536/175 gr Edge TLR
100 yds: 0 “ Drop	100 yds: 0 “ Drop	100 yds: 0 “ Drop
200 yds: 3.6 “ Drop	200 yds: 4 “ Drop	200 yds: 4.4 “ Drop
300 yds: 13.5 “ Drop	300 yds: 14.4 “ Drop	300 yds: 15.5 “ Drop
400 yds: 30.6 “ Drop	400 yds: 32 “ Drop	400 yds: 34.2 “ Drop
500 yds: 56.3 “ Drop	500 yds: 58 “ Drop	500 yds: 61.5 “ Drop

Looking at the numbers, it becomes absolutely clear that the .308 Winchester is a flatter shooting round when compared to the .300 blk. In fact, the .308 Win is way better than the .300 blk. However, the .300 blk is not really to blame because this is somewhat an apples to oranges comparison as far as the trajectory is concerned. 

The .300 blk is an overall shorter case with almost half the amount of power as the .308 Win. Since both cartridges use the same sized bullet, the .308 Win obviously has more fuel to propel the heavy bullet at higher speeds and farther. 

Additionally, you must also not forget that the .300 blk is very effective with short barrel rifles. Barrel lengths like nine inches do not provide significant burning time to achieve higher velocities. However, the performance of the .300 blk is not bad and quite considerable within a range of 250-300 yards. 

300 Blackout vs 308: Velocity & Kinetic Energy

The velocity and kinetic energy characteristics of a bullet are important in determining the effective range and suitable applications for a round to some extent. Faster bullets can be more accurately estimated for performance, especially at a long range. Additionally, the kinetic energy a bullet carries at a certain range is important in determining if it will be able to kill a specific game animal at varying ranges. 

300 Blackout

16” barrel/BC 0.290/110 gr Hornady V-Max	9” barrel/BC 0.251/120 gr Copper HP	16” barrel/BC 0.406/150 gr FMJ Boat-Tail
100 yds: 2,094 ft/s, 1,071 ft.lbs	100 yds: 1,799 ft/s, 863 ft.lbs	100 yds: 1,724 ft/s, 990 ft.lbs
200 yds: 1,834 ft/s, 821 ft.lbs	200 yds: 1,533 ft/s, 626 ft.lbs	200 yds: 1,561 ft/s, 811 ft.lbs
300 yds: 1,597 ft/s, 623 ft.lbs	300 yds: 1,307 ft/s, 455 ft.lbs	300 yds: 1,411 ft/s, 663 ft.lbs
400 yds: 1,389 ft/s, 471 ft.lbs	400 yds: 1,136 ft/s, 344 ft.lbs	400 yds: 1,282 ft/s, 547 ft.lbs
500 yds: 1,218 ft/s, 362 ft.lbs	500 yds: 1,024 ft/s, 279 ft.lbs	500 yds: 1,174 ft/s, 459 ft.lbs

308

24”barrel/BC 0.408/150 gr FMJ Boat-tail	24”barrel/BC 0.489/168 gr Berger Hybrid	24”barrel/BC 0.536/175 gr Edge TLR
100 yds: 2,597 ft/s, 2,246 ft.lbs	100 yds: 2,518 ft/s, 2,365 ft.lbs	100 yds: 2,437 ft/s, 2,308 ft.lbs
200 yds: 2,385 ft/s, 1894 ft.lbs	200 yds: 2,343 ft/s, 2,048 ft.lbs	200 yds: 2,280 ft/s, 2,021 ft.lbs
300 yds: 2,183 ft/s, 1,586 ft.lbs	300 yds: 2,176 ft/s, 1,766 ft.lbs	300 yds: 2,130 ft/s, 1,762 ft.lbs
400 yds: 1,990 ft/s, 1,319 ft.lbs	400 yds: 2,015 ft/s, 1,514 ft.lbs	400 yds: 1,984 ft/s, 1,530 ft.lbs
500 yds: 1,808 ft/s, 1,089 ft.lbs	500 yds: 1,860 ft/s, 1,291 ft.lbs	500 yds: 1,845 ft/s, 1,322 ft.lbs

The velocity characteristics of both these rounds are quite far apart. The barrel length indeed plays a significant role in deciding the velocity of a bullet. The .300 blk being shot from shorter barrels (and with lesser powder) shows far less velocity and a steep drop in its range as the range increases. 

.300 blk bullets fired from a long barrel stay supersonic out to 500 yards. Whereas shorter barrels bring that range down to just 400 yards. 

300 Blackout vs 308: Stopping Power

The stopping power of a bullet describes its capability to incapacitate or kill a target as quickly as possible and with the minimum number of rounds. The measure of stopping power is conducted by measuring the penetration and wound channel size of the bullet. These characteristics are measured using the sectional density and momentum values of the bullet. 

It is a general notion that bigger caliber bullets have better stopping power. Although that’s true in most cases, but not always. Which is where factors like sectional density and momentum come into play. 

300 Blackout vs 308: Momentum & Sectional Density

Before we dig deeper into the concept, take a quick look at the momentum and sectional density values of the .300 blk and .308 Win bullets side by side. 

16” barrel/BC 0.290/110 gr Hornady V-Max Sectional Density: 0.166	9” barrel/BC 0.251/120 gr Copper HP Sectional Density: 0.181	16” barrel/BC 0.406/150 gr FMJ Boat-Tail Sectional Density: 0.226
100 yds: 32 lb.ft-s	100 yds: 30 lb.ft-s	100 yds: 36 lb.ft-s
200 yds: 28 lb.ft-s	200 yds: 26 lb.ft-s	200 yds: 33 lb.ft-s
300 yds: 25 lb.ft-s	300 yds: 22 lb.ft-s	300 yds: 30 lb.ft-s
400 yds: 21 lb.ft-s	400 yds: 19 lb.ft-s	400 yds: 27 lb.ft-s
500 yds: 19 lb.ft-s	500 yds: 17 lb.ft-s	500 yds:  25 lb.ft-s

308

24”barrel/BC 0.408/150 gr FMJ Boat-tail Sectional Density: 0.266	24”barrel/BC 0.489/168 gr Berger Hybrid Sectional Density: 0.253	24”barrel/BC 0.536/175 gr Edge TLR Sectional Density: 0.264
100 yds: 55 lb.ft-s	100 yds: 60 lb.ft-s	100 yds: 60 lb.ft-s
200 yds: 51 lb.ft-s	200 yds: 56lb.ft-s	200 yds: 57 lb.ft-s
300 yds: 46 lb.ft-s	300 yds: 52 lb.ft-s	300 yds: 53 lb.ft-s
400 yds: 42 lb.ft-s	400 yds: 48 lb.ft-s	400 yds: 49 lb.ft-s
500 yds: 38 lb.ft-s	500 yds: 44 lb.ft-s	500 yds: 46 lb.ft-s

The sectional density (SD) of a bullet refers to the ratio of its mass and cross-sectional area. The higher the SD, the more penetration a bullet will offer. This calculation is the basis for segregating bullets suitable for hunting different classes of game animals (class 1, 2, 3, or 4) 

Bullets with SD between 0.100 to 0.200 are good for small varmints, SD between 0.210 to 0.260 is good for class 2 medium sized game like deer. SD between 0.270 and 0.300 are good for class 3 games like elk and anything above is good for even bigger games. 

Even smaller caliber bullets like the 7mm can have SD above .300 making them versatile. Talking about these two bullets here under comparison, you can clearly see that in heavy weight the .300 blk is a viable deer hunting round. Whereas the .308 is a great medium game round at the least and can tackle class 3 game with its heavy bullets. 

With an average momentum of about 30 lb-ft-s to take down a deer, the .300 blk is good for deer under 250 to 300 yards. Whereas the .308 is a very powerful round out to at least 600 yards. 

300 Blackout vs 308: Use Cases & Effective Range

Now comes the moment to understand the real-life implementation of these two rounds and what they are really good at. 

Tacti-cool Round vs Long Range Slayer

The .300 blk is a reincarnation of the .223 round into a .308 round that can be fired to the same rifle. As I already mentioned that this round was exclusively designed for short range engagements, the ballistics, velocity, and stopping power numbers confirm that. The .300 blk is a hard-hitting heavy caliber round that can be used with SBR and suppressors. That is something a special forces operative working CQB would love!

Talking about the .308 Win, apart from being a popular hunting round, it is also one of the most popular sniper rounds used by militaries around the world. The USMC accepts the effective range of the 7.62 NATO to be 1,000 yards. The .308 round will have an average drop of around 380 inches at that range and delivers around six-inch groups on average at that range with a good rifle and shooter. 

The .308 also has been widely used for competitions with several world records under its name. It is also quite popular in F-class competitions. 

Deer Round vs Anti-anything Round

The .300 blk is a deer slayer at best with an average bullet weights of 150 grains. However, with the heaviest 220-grain subsonic bullets, it can offer an SD of 0.331 and becomes viable for engaging dangerous big game animals at short range. I am clearly not advocating using it for such uses, but in my opinion, it can prove to be a great semi-auto mag-fed defense gun in bear country. 

The .308 Win has been an absolute favorite of the hunting community since it was introduced. It was also the ideal caliber for Col. Jeff Cooper, the legend behind inventing the scout rifle concept. With a wide range of available bullets and weights, the .308 Win can be used for anything from varmints to brown bears. 

Home Defense and Preppers

Technically, both these cartridges are suitable for tactical military applications. However, personally, I will not recommend either of these for home defense. That is because these are .30 caliber rounds with an effective penetration power and suitability for 250 yards plus uses. The overpenetration will be hazardous inside a house. Probably you should stick to handguns, shotguns, or just the AR-15. 

Additionally, as far as SHTF is concerned, you can trust either of these rounds. However, IMHO I’d always want to go with the .308 Win. 

300 Blackout vs 308: Costs, Availability, & Compatibility

After looking at the best applications, now let’s turn towards the pricing, availability, and upgrade factors for these calibers. 

Low Popularity vs Breakout Fame

Versatile Range of Rifles

Being short action cartridges, the .300 blk and .308 Win can be fired from bolt action or semi-auto rifles. This expands the range of rifles available for these rounds. Additionally, the .300 BLK’s compatibility with the AR-15 platform and the .308’s popularity (also chambering for the AR-10) opens up a huge sea of possibilities for the latest tech upgrades and aftermarket accessories. 

Bottom Line

The .300 Blackout is a fairly new cartridge on the market when compared with the old and reliable .308 Winchester. The .300 blk converts an AR-15 into a .308 inch bullet firing rifle at the cost of only the barrel. As far as ballistics are concerned, the .308 is way ahead of the .300 blk in terms of trajectory, energy, and stopping power. 

The .308 is a versatile round suitable for hunting almost any game and reaching out to long ranges of 1,000 yards. The .300 blk is good for short range uses (within 300 yards) where hard-hitting power is required and a short barrel is needed. Both are short action rounds and can be fired from semi-auto rifles. Although none of these can fully replace the other.