Size, Shape, and Weight Differences<\/h3>\n![\"5.56](\"https:\/\/www.ammunitiontogo.com\/lodge\/wp-content\/uploads\/5.56-vs-300-BLK-ammunition.jpg\" "\\"5.56")
A 5.56×45 cartridge (left) next to a 300 Blackout cartridge (right)<\/figcaption><\/figure>\nPhysically, there is an interesting comparison between these two cartridges. They have the exact same overall length and the same rim diameter, but if you hold them side-by-side, you can see very obvious differences; they are clearly not the same round.<\/p>\n
Although both have a total length of 2.26 inches, the casing of the NATO is 1.76 inches, while the Blackout\u2019s is roughly 1.37 inches. This means that the NATO has more space for propellant and less space for a bullet, while the Blackout has less space for propellant but a larger bullets.<\/p>\n
![\"Pulled](\"https:\/\/www.ammunitiontogo.com\/lodge\/wp-content\/uploads\/Pulled-bullets-of-300-BLK-vs-5.56.jpg\")
<\/p>\n
This difference is seen in their projectile sizes. .5.56 NATO has a standard size of 55 grain and maxes out around 65 grains. The Blackout, however, packs bullets as heavy as 260 grains or more.*<\/p>\n
*While the .300 AAC Blackout goes as high as 260 grains for some products, the cartridges with bullets in this weight are subsonic, which requires slow speeds. Essentially, to make up for low velocity, these cartridge pack extremely heavy projectiles.<\/p>\n
Availability and Pricing<\/h3>\n
This has less to do with the physical characteristics of the cartridges, and more to do with history and the market. The 5.56x45mm is a well-established cartridge used by shooters for decades. As such, there are numerous options from many different manufacturers. .300 Blackout, while gaining popularity, has only been around since about 2011, making it a newcomer to the market. As such, there are fewer options available.<\/p>\n
Also, the 5.56 is often found in bulk military surplus boxes<\/a>. This makes it an extremely affordable round for many shooters across the country.<\/p>\nBut what really matters to shooters is not size or looks, but performance. For that, we need look at velocity, energy, and trajectory.<\/p>\n
\n \n \n \n \n \n \n \n ![\"product\"](\"https:\/\/static-cdn.ammunitiontogo.com\/pimages\/image\/512x\/e0266470459c8672771a1cb2d1bebeb3\/e\/c\/ec9d4083b47f367719b323b3785234d3_4.jpg\")
\n <\/div>\n \n \n $511.95 <\/div>\n \n $489.95 <\/div>\n <\/div>\n <\/div>\n \n ![\"logo\"](\"https:\/\/www.ammunitiontogo.com\/lodge\/wp-content\/themes\/atg\/assets\/img\/mc-logo-gray.svg\")
\n <\/div>\n <\/div>\n \n 1000rds \u2013 5.56x45 PMC X-TAC 62gr. FMJ M855 Ammo <\/div>\n <\/div>\n <\/a>\n <\/div>\n \n \n \n \n \n \n ![\"product\"](\"https:\/\/static-cdn.ammunitiontogo.com\/pimages\/image\/512x\/e0266470459c8672771a1cb2d1bebeb3\/2\/d\/2d1a8c7de34d7d6492d302b3a3d65dc2_4.jpg\")
\n <\/div>\n \n \n $14.95 <\/div>\n <\/div>\n <\/div>\n \n \n <\/div>\n <\/div>\n \n 20rds \u2013 5.56x45 PMC X-TAC 62gr. FMJ M855 Ammo <\/div>\n <\/div>\n <\/a>\n <\/div>\n \n \n \n \n \n \n ![\"product\"](\"https:\/\/static-cdn.ammunitiontogo.com\/pimages\/image\/512x\/e0266470459c8672771a1cb2d1bebeb3\/0\/e\/0e75de0ae3026cd7968e107734f020ee_4.jpg\")
\n <\/div>\n \n \n $13.95 <\/div>\n <\/div>\n <\/div>\n \n \n <\/div>\n <\/div>\n \n 20rds - 5.56 PMC X-TAC 55gr. (XP193) Full Metal Jacket Ammo <\/div>\n <\/div>\n <\/a>\n <\/div>\n \n \n \n \n \n \n ![\"product\"](\"https:\/\/static-cdn.ammunitiontogo.com\/pimages\/image\/512x\/e0266470459c8672771a1cb2d1bebeb3\/0\/e\/0e4e04ae853885f78da581939c589291_4.jpg\")
\n <\/div>\n \n \n $484.95 <\/div>\n \n $459.95 <\/div>\n <\/div>\n <\/div>\n \n \n <\/div>\n <\/div>\n \n 1000rds \u2013 5.56x45 PMC X-TAC 55gr. FMJBT Ammo <\/div>\n <\/div>\n <\/a>\n <\/div>\n \n \n \n \n \n \n ![\"product\"](\"https:\/\/static-cdn.ammunitiontogo.com\/pimages\/image\/512x\/e0266470459c8672771a1cb2d1bebeb3\/3\/f\/3f173d7e691214c2723ed8a248bd10d6_4.jpg\")
\n <\/div>\n \n \n $339.95 <\/div>\n <\/div>\n <\/div>\n \n \n <\/div>\n <\/div>\n \n 600rds \u2013 5.56 PMC X-TAC Battle Pack 62gr. FMJ M855 Green Tip - LAP Ammo <\/div>\n <\/div>\n <\/a>\n <\/div>\n \n \n \n \n \n \n ![\"product\"](\"https:\/\/static-cdn.ammunitiontogo.com\/pimages\/image\/512x\/e0266470459c8672771a1cb2d1bebeb3\/8\/9\/892b6c557427c03c7b4ceb32863e8545_4.jpg\")
\n <\/div>\n \n \n $97.95 <\/div>\n <\/div>\n <\/div>\n \n \n <\/div>\n <\/div>\n \n 50rds - 5.56 Black Hills 62gr. TSX HP Ammo <\/div>\n <\/div>\n <\/a>\n <\/div>\n \n \n \n \n \n \n ![\"product\"](\"https:\/\/static-cdn.ammunitiontogo.com\/pimages\/image\/512x\/e0266470459c8672771a1cb2d1bebeb3\/b\/7\/b78f775f335a36c92fc2849a2855647a.jpg\")
\n <\/div>\n \n \n $104.95 <\/div>\n <\/div>\n <\/div>\n \n \n <\/div>\n <\/div>\n \n 50rds - 5.56 Nato Black Hills Barnes TSX 50gr. Hollow Point Ammo <\/div>\n <\/div>\n <\/a>\n <\/div>\n \n \n \n \n \n \n ![\"product\"](\"https:\/\/static-cdn.ammunitiontogo.com\/pimages\/image\/512x\/e0266470459c8672771a1cb2d1bebeb3\/9\/2\/92ff233b5bdaadf8698146a4a276c538.jpg\")
\n <\/div>\n \n \n $949.95 <\/div>\n <\/div>\n <\/div>\n \n \n <\/div>\n <\/div>\n \n 500rds \u2013 5.56x45 Black Hills 50gr. TSX Ammo <\/div>\n <\/div>\n <\/a>\n <\/div>\n \n \n \n \n \n \n ![\"product\"](\"https:\/\/static-cdn.ammunitiontogo.com\/pimages\/image\/512x\/e0266470459c8672771a1cb2d1bebeb3\/c\/f\/cf5575050b8c0e94b08377adfc32e96f.jpg\")
\n <\/div>\n \n \n $19.95 <\/div>\n <\/div>\n <\/div>\n \n \n <\/div>\n <\/div>\n \n 20rds \u2013 300 AAC Blackout Sellier & Bellot 124gr. FMJ Ammo <\/div>\n <\/div>\n <\/a>\n <\/div>\n <\/div>\n \n \n ![\"left](\"https:\/\/www.ammunitiontogo.com\/lodge\/wp-content\/themes\/atg\/assets\/img\/mc-arrow-left.svg\")
\n <\/div>\n \n \n 1 <\/div>\n \n 2 <\/div>\n \n 3 <\/div>\n \n 4 <\/div>\n \n 5 <\/div>\n <\/div>\n \n ![\"right](\"https:\/\/www.ammunitiontogo.com\/lodge\/wp-content\/themes\/atg\/assets\/img\/mc-arrow-right.svg\")
\n <\/div>\n <\/div>\n<\/div>\n300 BLK vs 5.56: Performance<\/h2>\n
![\"Shooting](\"https:\/\/www.ammunitiontogo.com\/lodge\/wp-content\/uploads\/Shooting-an-ar-15-at-the-range.jpg\")
<\/p>\n
For our performance comparison, we\u2019ll look at six total cartridges, two each from a different manufacturer. In all three comparisons, we tried to use similar products that had the same purpose, such as target shooting or varmint hunting. This is a small sample, but we chose typical rounds that should give us a strong understanding of the 5.56 NATO vs the .300 Blackout.<\/p>\n
First, let\u2019s see how these cartridges perform for speed\u2026<\/p>\n\n
\n\n\n\t<\/td> Muzzle Velocity (fps)<\/th> 200-yard Velocity (fps)<\/th>\n<\/tr>\n<\/thead>\n \n\n\t5.56 - Federal 55 Gr. FMJBT<\/td> 3,165<\/td> 2,412<\/td>\n<\/tr>\n \n\t300 BLK - Federal 150 Gr. FMJBT<\/td> 1,900<\/td> 1,561<\/td>\n<\/tr>\n \n\t<\/td> <\/td> <\/td>\n<\/tr>\n \n\t5.56 - Hornady 62 Gr. FMJ<\/td> 3,060<\/td> 2,394<\/td>\n<\/tr>\n \n\t300 BLK - Hornady 125 Gr. FMJ<\/td> 2,175<\/td> 1,591<\/td>\n<\/tr>\n \n\t<\/td> <\/td> <\/td>\n<\/tr>\n \n\t5.56 - Winchester 77 Gr. BTHP<\/td> 2,750<\/td> 2,240<\/td>\n<\/tr>\n \n\t300 BLK - Winchester 125 Gr. OTM<\/td> 2,185<\/td> 1,632<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\nIf high velocity is a priority, there\u2019s no question that the 5.56 is your better choice. In all three comparisons, the 5.56 NATO had faster speeds at the muzzle and at 200 yards, and in most cases, it wasn\u2019t even close.<\/p>\n
The slowest 5.56 in our group had a muzzle speed of 2,750 feet-per-second (fps), while the fastest Blackout was below 2,200 fps. At distance, the NATO maintained decent speed, well over 2,200 fps, while. The Blackout dipped to around 1,600 fps.<\/p>\n
For both close range and long distance, the 5.56 is going to be your faster option.<\/p>\n
Winner: 5.56x45mm NATO<\/strong><\/p>\nEnergy<\/h3>\n
Speed is great, but if you are hunting with this cartridge, of if you want a greater impact at the target, you need to consider energies as well. There was a clear winner in velocity, but when we move to energy, will the speeds of the 5.56 make the difference, or will the heavier bullets in the .300 Blackout create higher impact energies?<\/p>\n\n
\n\n\n\t<\/td> Muzzle Energy (Ft-lbs)<\/th> 200-yard Energy (Ft-lbs)<\/th>\n<\/tr>\n<\/thead>\n \n\n\t5.56 - Federal 55 Gr. FMJBT<\/td> 1,223<\/td> 711<\/td>\n<\/tr>\n \n\t300 BLK - Federal 150 Gr. FMJBT<\/td> 1,202<\/td> 811<\/td>\n<\/tr>\n \n\t<\/td> <\/td> <\/td>\n<\/tr>\n \n\t5.56 - Hornady 62 Gr. FMJ<\/td> 1,289<\/td> 789<\/td>\n<\/tr>\n \n\t300 BLK - Hornady 125 Gr. FMJ<\/td> 1,313<\/td> 703<\/td>\n<\/tr>\n \n\t<\/td> <\/td> <\/td>\n<\/tr>\n \n\t5.56 - Winchester 77 Gr. BTHP<\/td> 1,293<\/td> 858<\/td>\n<\/tr>\n \n\t300 BLK - Winchester 125 Gr. OTM<\/td> 1,325<\/td> 793<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\nFrom the muzzle, there is really no clear winner between the two. They were all within 30 ft-lbs of each other, and the 5.56 was more powerful in one comparison but weaker in the other two.<\/p>\n
At a distance, we see some difference, but not much. At 200 yards, the 5.56 was stronger in two comparisons but weaker in one. Clearly you can\u2019t say that one is more powerful than the other. This is an interesting result, as each one has a potential advantage for power; the 5.56 is faster, but the .300 Blackout has a heavier projectile. In the end, this results in a draw.<\/p>\n
Winner: Draw<\/strong><\/p>\n300 Blackout vs 5.56 Trajectory<\/h3>\n
Whether you are hunting or target shooting, you are likely concerned with the flatness and overall accuracy of these cartridges. While the information from manufacturers may not be as consistent, they do provide data on flight trajectory.<\/p>\n
If you know much about the physics of bullet flight, you can likely guess which one has flatter trajectories. The 5.56, with faster speeds and lighter projectiles, is easily the flatter-shooting round.<\/p>\n
The Federal products we highlighted provide the perfect example. When zeroed to 100 yards, the 55-grain NATO drops only 3 inches. The 150-grain Blackout, on the other hand, drops 10 inches. At 300 yards, the drop is 12.1 for the NATO and 34.7 for the Blackout. The same trend is repeated in other cartridges that have a consistent comparison.<\/p>\n
Winner: .300 Blackout<\/strong><\/p>\nClick here for more in-depth and load specific 300 Blackout Ballistics data<\/a>.<\/p>\nChoosing the 5.56x45mm or the .300 AAC Blackout<\/h3>\nChoose the 5.56 if You Want\u2026<\/h4>\n
Physically, there is an interesting comparison between these two cartridges. They have the exact same overall length and the same rim diameter, but if you hold them side-by-side, you can see very obvious differences; they are clearly not the same round.<\/p>\n
Although both have a total length of 2.26 inches, the casing of the NATO is 1.76 inches, while the Blackout\u2019s is roughly 1.37 inches. This means that the NATO has more space for propellant and less space for a bullet, while the Blackout has less space for propellant but a larger bullets.<\/p>\n
<\/p>\n
This difference is seen in their projectile sizes. .5.56 NATO has a standard size of 55 grain and maxes out around 65 grains. The Blackout, however, packs bullets as heavy as 260 grains or more.*<\/p>\n
*While the .300 AAC Blackout goes as high as 260 grains for some products, the cartridges with bullets in this weight are subsonic, which requires slow speeds. Essentially, to make up for low velocity, these cartridge pack extremely heavy projectiles.<\/p>\n
Availability and Pricing<\/h3>\n
This has less to do with the physical characteristics of the cartridges, and more to do with history and the market. The 5.56x45mm is a well-established cartridge used by shooters for decades. As such, there are numerous options from many different manufacturers. .300 Blackout, while gaining popularity, has only been around since about 2011, making it a newcomer to the market. As such, there are fewer options available.<\/p>\n
Also, the 5.56 is often found in bulk military surplus boxes<\/a>. This makes it an extremely affordable round for many shooters across the country.<\/p>\n But what really matters to shooters is not size or looks, but performance. For that, we need look at velocity, energy, and trajectory.<\/p>\n For our performance comparison, we\u2019ll look at six total cartridges, two each from a different manufacturer. In all three comparisons, we tried to use similar products that had the same purpose, such as target shooting or varmint hunting. This is a small sample, but we chose typical rounds that should give us a strong understanding of the 5.56 NATO vs the .300 Blackout.<\/p>\n First, let\u2019s see how these cartridges perform for speed\u2026<\/p>\n\n If high velocity is a priority, there\u2019s no question that the 5.56 is your better choice. In all three comparisons, the 5.56 NATO had faster speeds at the muzzle and at 200 yards, and in most cases, it wasn\u2019t even close.<\/p>\n The slowest 5.56 in our group had a muzzle speed of 2,750 feet-per-second (fps), while the fastest Blackout was below 2,200 fps. At distance, the NATO maintained decent speed, well over 2,200 fps, while. The Blackout dipped to around 1,600 fps.<\/p>\n For both close range and long distance, the 5.56 is going to be your faster option.<\/p>\n Winner: 5.56x45mm NATO<\/strong><\/p>\n Speed is great, but if you are hunting with this cartridge, of if you want a greater impact at the target, you need to consider energies as well. There was a clear winner in velocity, but when we move to energy, will the speeds of the 5.56 make the difference, or will the heavier bullets in the .300 Blackout create higher impact energies?<\/p>\n\n From the muzzle, there is really no clear winner between the two. They were all within 30 ft-lbs of each other, and the 5.56 was more powerful in one comparison but weaker in the other two.<\/p>\n At a distance, we see some difference, but not much. At 200 yards, the 5.56 was stronger in two comparisons but weaker in one. Clearly you can\u2019t say that one is more powerful than the other. This is an interesting result, as each one has a potential advantage for power; the 5.56 is faster, but the .300 Blackout has a heavier projectile. In the end, this results in a draw.<\/p>\n Winner: Draw<\/strong><\/p>\n Whether you are hunting or target shooting, you are likely concerned with the flatness and overall accuracy of these cartridges. While the information from manufacturers may not be as consistent, they do provide data on flight trajectory.<\/p>\n If you know much about the physics of bullet flight, you can likely guess which one has flatter trajectories. The 5.56, with faster speeds and lighter projectiles, is easily the flatter-shooting round.<\/p>\n The Federal products we highlighted provide the perfect example. When zeroed to 100 yards, the 55-grain NATO drops only 3 inches. The 150-grain Blackout, on the other hand, drops 10 inches. At 300 yards, the drop is 12.1 for the NATO and 34.7 for the Blackout. The same trend is repeated in other cartridges that have a consistent comparison.<\/p>\n Winner: .300 Blackout<\/strong><\/p>\n Click here for more in-depth and load specific 300 Blackout Ballistics data<\/a>.<\/p>\n\n <\/div>\n \n <\/div>\n <\/div>\n \n <\/div>\n \n <\/div>\n <\/div>\n \n <\/div>\n \n <\/div>\n <\/div>\n \n <\/div>\n \n <\/div>\n <\/div>\n \n <\/div>\n \n <\/div>\n <\/div>\n \n <\/div>\n \n <\/div>\n <\/div>\n \n <\/div>\n \n <\/div>\n <\/div>\n \n <\/div>\n \n <\/div>\n <\/div>\n \n <\/div>\n \n <\/div>\n <\/div>\n \n <\/div>\n \n <\/div>\n <\/div>\n<\/div>\n300 BLK vs 5.56: Performance<\/h2>\n
<\/p>\n\n\n
\n\t \n<\/td> Muzzle Velocity (fps)<\/th> 200-yard Velocity (fps)<\/th>\n<\/tr>\n<\/thead>\n \n\t 5.56 - Federal 55 Gr. FMJBT<\/td> 3,165<\/td> 2,412<\/td>\n<\/tr>\n \n\t 300 BLK - Federal 150 Gr. FMJBT<\/td> 1,900<\/td> 1,561<\/td>\n<\/tr>\n \n\t <\/td> <\/td> <\/td>\n<\/tr>\n \n\t 5.56 - Hornady 62 Gr. FMJ<\/td> 3,060<\/td> 2,394<\/td>\n<\/tr>\n \n\t 300 BLK - Hornady 125 Gr. FMJ<\/td> 2,175<\/td> 1,591<\/td>\n<\/tr>\n \n\t <\/td> <\/td> <\/td>\n<\/tr>\n \n\t 5.56 - Winchester 77 Gr. BTHP<\/td> 2,750<\/td> 2,240<\/td>\n<\/tr>\n \n\t 300 BLK - Winchester 125 Gr. OTM<\/td> 2,185<\/td> 1,632<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n Energy<\/h3>\n
\n\n
\n\t \n<\/td> Muzzle Energy (Ft-lbs)<\/th> 200-yard Energy (Ft-lbs)<\/th>\n<\/tr>\n<\/thead>\n \n\t 5.56 - Federal 55 Gr. FMJBT<\/td> 1,223<\/td> 711<\/td>\n<\/tr>\n \n\t 300 BLK - Federal 150 Gr. FMJBT<\/td> 1,202<\/td> 811<\/td>\n<\/tr>\n \n\t <\/td> <\/td> <\/td>\n<\/tr>\n \n\t 5.56 - Hornady 62 Gr. FMJ<\/td> 1,289<\/td> 789<\/td>\n<\/tr>\n \n\t 300 BLK - Hornady 125 Gr. FMJ<\/td> 1,313<\/td> 703<\/td>\n<\/tr>\n \n\t <\/td> <\/td> <\/td>\n<\/tr>\n \n\t 5.56 - Winchester 77 Gr. BTHP<\/td> 1,293<\/td> 858<\/td>\n<\/tr>\n \n\t 300 BLK - Winchester 125 Gr. OTM<\/td> 1,325<\/td> 793<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n 300 Blackout vs 5.56 Trajectory<\/h3>\n
Choosing the 5.56x45mm or the .300 AAC Blackout<\/h3>\n
Choose the 5.56 if You Want\u2026<\/h4>\n