The .300 Blackout was designed as a solution to quickly turn a 5.56 mm caliber AR into a .30 caliber AR. The idea was amazing, and it was planned for the special forces wing of the military but did not work out that well. However, the civilian firearms community took it with both hands, but does it really perform on its promises? 

Similarly, the 6.5 Creedmoor was also developed to serve as a long range combat round for the military, and it does serve that purpose to some extent. It is mostly seen as a low-recoil alternative to some time-tested long range rounds, and it does present itself as a better option. 

This guide here will be comparing these two popular cartridges and will try to find out their areas of excellence and mediocrity. 

TL;DR: 300 Blackout vs 6.5 Creedmoor

A quick pros and cons comparison for these two cartridges to get you get a broad idea.

300 Blackout Overview

The .300 AAC Blackout, also known as the .300 Blk or .300 Blackout, is a rimless, bottlenecked, intermediate rifle cartridge, developed in the United States by the Advanced Armament Corporation (AAC). This round was designed in 2010 for the M4 platform. The purpose was to keep the 5.56 NATO bolts and parts intact and achieve ballistic performance similar to the 7.62×39 mm round. 

In simpler words, the objective was to equip the M4 rifle with the power of a .30 caliber round, without compromising on the magazine capacity, and with maximum interoperability. This round was said to be developed for the special forces who wanted a harder hitting round for close quarter battles. A round that worked well with suppressors, and could surpass the 9 mm rounds in power. 

This round was approved by SAAMI in 2011 and has become quite popular among the AR-15 platform users. Since it allows them to quickly change their .223 rifle into a .30 caliber rifle. Although the round performs great in close quarters and at medium range, it has still not been officially adopted by the U.S Military. .300 Blk is a very popular caliber for the AR-15 platform, and its upper receivers are sold in large numbers. 

6.5 Creedmoor Overview

The 6.5 Creedmoor, also known as the 6.5 CRDMR or the 6.5 CM, is a centerfire rifle cartridge introduced by Hornady in 2007. It was developed under a collaboration between Hornady and Creedmoor, hence the name. This round is a modification (necked-down version) of the .30 Thompson Center cartridge and is capable of achieving a trajectory similar to the .300 Win Mag. It is ballistically comparable to .260 Winchester and 6.5×47 mm Lapua rounds. 

This round was exclusively designed for long range shooting, and although it achieves lesser velocity than its 6.5 mm counterparts, the short-action design is a great benefit. This allows this round to be cycled quickly and used in semi-auto rifles. Additionally, it is used by some sniper and special forces units of the military. 

As far as the civilian population is concerned, the 6.5 Creedmoor is a popular competition and slightly popular hunting round. The .243 inch diameter bullets are suitable for deer-sized game animals, and some smaller critters as well. 

300 Blackout vs 6.5 Creedmoor: Cartridge Specs

	300 Blackout	6.5 Creedmoor
Bullet Diameter	0.308 in (7.8 mm)	.2644 in (6.72 mm)
Neck Diameter	0.334 in (8.5 mm)	.2950 in (7.49 mm)
Base Diameter	0.376 in (9.6 mm)	4703 in (11.95 mm)
Case Length	1.368 in (34.7 mm)	1.920 in (48.8 mm)
Overall Length	2.26 in (57 mm)	2.825 in (71.8 mm)
Case Capacity	21 grains	52.5 grains
Max Pressure (SAAMI)	55,000 psi	62,000 psi
Typical Casing Material	Brass	Brass
Typical Bullet Weight (gr)	110-150 grains	120-150 grains

The .300 blk and 6.5 CM are quite different when it comes to overall dimensions. The .300 blk fires a .308 inch diameter, whereas, the 6.5 CM uses a .264 inch diameter bullet. This causes these bullets to have different stopping power characteristics, which we will be looking at in the next sections. 

Although the 6.5 CM is a fatter case, the neck size for the .300 blk is more with a steeper shoulder angle. The design of the neck is pertinent to the range, velocity, and cycling characteristics of these cartridges. 

Looking at the overall length, the .300 blk is almost half an inch shorter than the 6.5 CM. It has less than 50% of the case capacity and is loaded at a lesser pressure. 

The .300 blk has a wide range of selection when it comes to bullet weights, which can start from as low as 78 grains and go all the way up to 220 grains for subsonic loads. The 110-150 grain weights are mostly preferred for hunting and the heavier loads for defense. 

The 6.5 CM has a less wide range of bullet weights ranging between 120 to 150 grains, with the best bullet weight being 143 grains for long range engagements. The ballistic coefficients of the 6.5 CM are always better because the round was designed for long range engagements. 

300 Blackout vs 6.5 Creedmoor: Ballistics

Now let’s take a look at the ballistics data for these two cartridges. This data has been compiled using the most common bullet types and weights, and out to a distance that will elaborate on their maximum potential. 

300 Blackout vs 6.5 Creedmoor: Trajectory

Here is a table comparing the trajectory data of the most common bullets for these cartridges, out to a distance of 1,000 yards. 

.300 blk

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
1,000 yds: 806.3 “ Drop	1,000 yds: 1075.6 “ Drop	1,000 yds: 902.9 “ Drop

6.5 Creedmoor

24” barrel/BC 0.497/120 gr Trophy Copper	24” barrel/BC 0.365/130 gr Barnes Triple Shock-X	24” barrel/BC 0.509/140 gr Nosler Accubond
150 yds: 1“ Drop	150 yds: 1.1“ Drop	150 yds: 1.3“ Drop
200 yds: 3.3“ Drop	200 yds: 3.7“ Drop	200 yds: 4.1“ Drop
300 yds: 12.1“ Drop	300 yds: 13.9“ Drop	300 yds: 14.6“ Drop
400 yds: 27.4“ Drop	400 yds: 31.6“ Drop	400 yds: 32.4“ Drop
500 yds: 49.9“ Drop	500 yds: 59.3“ Drop	500 yds: 58.5“ Drop
1,000 yds: 327“ Drop	1,000 yds: 451.6“ Drop	1,000 yds: 381“ Drop

The .300 blk rounds have an average drop of about 8.5 inches at 200 yards, compared to the 3.5 inches drop for the 6.5 CM. So the flatter trajectory characteristics of the 6.5 CM start showing out almost instantly. 

The data clearly shows us that the drop for the .300 blk is acceptable only out to 300 yards, and beyond that, the bullet quickly begins to descend south. An average drop of 68 inches at 400 yards, and an average of 125 inches at 500 yards indicates that this cartridge is only meant for short to medium range accuracy. 

Moving on to the 6.5 Creedmoor, the rounds show exceptional trajectory characteristics and shoot almost flat out to 250 yards. The lightweight bullets show an amazingly flat trajectory at longer distances, with an average drop of just 350 inches at 1,000 yards which is great. Especially when you look at the short action dimensions, lower recoil, and lightweight rifles for the 6.5 CM. 

Since the 6.5 CM is a popular mainstream cartridge, there are many bullet options available for it on the market. Additionally, the 6.5 CM are always aerodynamically more stable than the .300 blk in comparable bullet weights. 

300 Blackout vs 6.5 Creedmoor: Velocity & Kinetic Energy

A tabular representation of the velocity and energy data of these rounds out to a distance of 1,000 yards.

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
150 yds: 1,961 ft/s, 940 ft.lbs	150 yds: 1,799 ft/s, 863 ft.lbs	150 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
1,000 yds: 846 ft/s, 175 ft.lbs	1,000 yds: 752 ft/s, 151 ft.lbs	1,000 yds: 897 ft/s, 268 ft.lbs

6.5 Creedmoor

24” barrel/BC 0.497/120 gr Trophy Copper	24” barrel/BC 0.365/130 gr Barnes Triple Shock-X	24” barrel/BC 0.509/140 gr Nosler Accubond
150 yds: 2,599 ft/s, 1,799 ft.lbs	150 yds: 2,457 ft/s, 1,742 ft.lbs	150 yds: 2,416 ft/s, 1,815 ft.lbs
200 yds: 2,510 ft/s, 1,679 ft.lbs	200 yds: 2,341 ft/s, 1,581 ft.lbs	200 yds: 2,334 ft/s, 1,693 ft.lbs
300 yds: 2,338 ft/s, 1,457 ft.lbs	300 yds: 2,118 ft/s, 1,294 ft.lbs	300 yds: 2,173 ft/s, 1,467 ft.lbs
400 yds: 2,174 ft/s, 1,259 ft.lbs	400 yds: 1,906 ft/s, 1,049 ft.lbs	400 yds: 2,018 ft/s, 1,266 ft.lbs
500 yds: 2,015 ft/s, 1,082 ft.lbs	500 yds: 1,711 ft/s, 845 ft.lbs	500 yds: 1,870 ft/s, 1,086 ft.lbs
1,000 yds: 1,349 ft/s, 485 ft.lbs	1,000 yds: 1,047 ft/s, 316 ft.lbs	1,000 yds: 1,264 ft/s, 496 ft.lbs

The velocity data clearly shows us that the .300 blk stays supersonic out to 500-600 yards, whereas the 6.5 CM maintains that speed out to 1,200 yards and even more. The distance out to which a round retains its supersonic speed tells us that the accuracy of a round is more predictable out to that distance. 

Although the velocity data for the .300 blk tells us that the round can be accurate out to 500 yards, the trajectory data does not concur with that. Additionally, the heavier .300 blk rounds like the 200 and 220-grain bullets are meant to be supersonic for use with suppressors.

The 6.5 CM is a long range round, and so the velocity has to be supersonic out to long distances. Coupled with the better aerodynamics and trajectory, the 6.5 CM needs lesser adjustments and is more accurate at long range. 

The .300 blk is clearly not a deer round according to acceptable hunting standards which say that a minimum of 1,000 fpe is required to harvest deer, and a minimum of 1,500 fpe is appropriate for the elk-sized game. However, it is a great small-game killer and a perfect hog medicine with that kind of power. 

The 6.5 CM carries enough energy to harvest deer at 500 yards, and take down elk at 250 yards. However, the size of the bullet (0.264 inches) does not make it suitable for that. We’ll learn more about that in the next section. 

300 Blackout vs 6.5 Creedmoor: Stopping Power

The stopping power of a bullet explains to us its capability to stop or incapacitate a target as quickly as possible. The harder a bullet hits, the better will be the stopping power. However, rather than guesstimating, the two most appropriate factors to find this out are the momentum and sectional density. 

300 Blackouts vs 6.5 Creedmoor: Momentum & Sectional Density

Here is the data explaining the momentum values for these bullets at different distances out to 1,000 yards. 

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
1,000 yds: 13 ft.lb-s	1,000 yds: 11 ft.lb-s	1,000 yds: 14 ft.lb-s

6.5 Creedmoor

24” barrel/BC 0.497/120 gr Trophy Copper Sectional Density: 0.246	24” barrel/BC 0.365/130 gr Barnes Triple Shock-X Sectional Density: 0.266	24” barrel/BC 0.509/140 gr Nosler Accubond Sectional Density: 0.287
150 yds: 44 ft.lb-s	150 yds: 45 ft.lb-s	150 yds: 48 ft.lb-s
200 yds: 43 ft.lb-s	200 yds: 43 ft.lb-s	200 yds: 46 ft.lb-s
300 yds: 40 ft.lb-s	300 yds: 39 ft.lb-s	300 yds: 43 ft.lb-s
400 yds: 37 ft.lb-s	400 yds: 35 ft.lb-s	400 yds: 40 ft.lb-s
500 yds: 34 ft.lb-s	500 yds: 31 ft.lb-s	500 yds: 37 ft.lb-s
1,000 yds: 23 ft.lb-s	1,000 yds: 19 ft.lb-s	1,000 yds: 25 ft.lb-s

The Sectional Density (SD) of a bullet is the ratio of its mass and cross-sectional area. This value is the easiest representation of the penetrating power of an object. The higher the value of SD, the more penetration will be achieved by a bullet, because a higher mass will get focused on a smaller area. 

The SD of 0.230 to 0.260 is considered best for hunting deer-sized game, anything less is for smaller game, and anything higher is for bigger game. While the lightweight bullets for the .300 blk have a lower SD suitable for only small game, the heavier bullets can handle the deer-sized game. 

On the other hand, the 6.5 CM has SD values which show that it is a great deer hunting round, and the heavier loads can also be used for bigger game animals with the heavy 140+ grain bullets. 

Another factor impacting the stopping power is momentum, which is the measure of the effectiveness of energy transfer. The higher the value of momentum, the bigger the wound cavity. The .300 blk delivers amazing momentum with the heavy bullets (150+ grains), but the lightweight loads are not very effective beyond 300 yards. 

The 6.5 CM has amazing momentum value and delivers similar momentum at 1,000 yards, what the .300 blk delivers at 400. 

300 Blackout vs 6.5 Creedmoor: Use Cases & Effective Range

The .300 blk and 6.5 CM were designed for different purposes, and it is imperative to understand the best applications of each to use them effectively. 

Small and Medium Game Hunting

The .300 blk is a perfect cartridge for hunting small to medium-sized game animals. Since it is an interchangeable caliber with the .223 Remington, the round is easily capable of taking down small game and handles medium game up to some range. 

For example, our energy data showed that the .300 blk did not have enough energy to kill a deer just after 150 yards. Now I will not consider the 300 blk a great round for deer, but if the quarry is within 120-150 yards, you can give it a shot and be successful. However, the .300 blk is a perfect hog medicine.

The 6.5 CM is a perfect deer hunting round, and the lighter bullets are also not overkilled for small game animals. Additionally, the .300 blk has almost 40% less recoil than the 6.5 CM, so make sure to consider that as well. 

Big Game Hunting

The .300 blk barely qualifies as a deer hunting round, and that too within a very short range, so it is not very great or reliable for hunting big game, and there are many better options out there. The 6.5 CM on the other hand is a good big game hunting round and carries enough energy to take down an elk or moose at 300 yards. 

With the right shot placement and within the right range, the 6.5 CM is an amazing big game hunting round. However, some people consider the .264 inch diameter bullet to be a bit small in diameter to reliably harvest big game, but the thing is that it works. 

Long Range Uses

The .300 blk is not a long range cartridge by any means possible. Its trajectory is just awful beyond 300 yards, and the round is not to blame because it was not designed for long range. Contrastingly, the 6.5 CM was exclusively designed for long range use and works great at 1,000 – 1500 yards. It even surpasses cartridges like the .308 Win in performance at long range. 

Tactical and Self Defense 

The .300 blk is an amazing selection for tactical applications like CQB. In fact, it was developed as a quick replacement for the 5.56 NATO M4 rifles and to increase their hitting power. The subsonic rounds work perfectly with short barreled rifles and with suppressors. Whereas the 6.5 CM is suitable for longer barrels and rifles, and although it can work effectively on close quarters, overpenetration can become a problem. 

300 Blackout vs 6.5 Creedmoor: Costs, Availability, & Compatibility

Take a quick peek into the cost and availability of ammo, and rifle options for these two cartridges. 

Inexpensive vs Premium But Uncertain Availability

The .300 blk ammo can be found at $1 to $2.5 per round, whereas the 6.5 CM retails at anywhere between $2.5 to $5 per round. The .300 blk can be a bit hard to find sometimes because it is neither a very popular hunting cartridge nor a popular tactical cartridge. 

The 6.5 CM has gained a lot of popularity in recent times as a hunting cartridge, but the availability slims down during the hunting season. Additionally, the recent Covid-19 pandemic shopping times have taught us a good lesson to always be prepared and have backup ammo. 

Limited vs Wide Range of Options

The .300 blk is a somewhat popular cartridge, but not too widespread to have a ton of ammo options available for it. The round offers just a handful of factory loads and options in bullet type and weights. The 6.5 CM has a wide range of ammo options and can be found in almost 15 different bullet types and many bullet weights. 

As far as rifle options are concerned, both these cartridges have several rifles to choose from. However, the .300 blk mostly sticks to semi-auto, the 6.5 CM can be found in many semi-auto and bolt action versions. 

Bottom Line

The .300 blk is an intermediate rifle cartridge that was designed to supplement the power of the 5.56 NATO M4 platform, and quickly convert it into a .30 caliber rifle with hard-hitting power, interchangeable parts, and the same mag capacity. It is a great close-quarters round and suitable for hunting small and medium-sized game. 

The 6.5 CM was exclusively designed for long range and is a great alternative to many long range cartridges with its smaller action and lesser recoil. This round is capable of taking down big game and delivering amazing accuracy at 1,000 – 1,200 yards.