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5.56x45mm vs 50 Beowulf

5.56 NATO VS 50 beowulf Blog Feature

Welcome back  to True Shot Academy. Today we wanted to go over the 5.56x45mm and the .50 Beowulf. The 5.56x45mm is the well-known and industry standard chambering for AR-15-styled rifles while the .50 Beowulf is a more exotic chambering. Now let’s get into the two cartridges.


Brief Background of the Calibers

The 5.56x45mm cartridge has been a long-standing military cartridge that has seen widespread military usage as a NATO standardized round. One can often find 5.56x45mm chambered firearms in the form of AR-15s with other designs such as Ruger Mini 14s, FN Herstal SCAR 16s, and even AK-pattern rifles utilizing the cartridge.

The .50 Beowulf cartridge is the brainchild of Alexander Arms’ Bill Alexander. The round allows one to utilize a high caliber cartridge in an AR-15 platform, making it a popular choice for hunters who wish to bring an AR with them into the field.


Common Receivers

An AR-15 can be chambered in 5.56x45mm and .50 Beowulf alike. In a true testament to the modularity of the platform, both chamberings utilize the same upper and lower receivers.

The main differences lie in having an appropriate barrel and bolt carrier group to accommodate either chambering. This means that you could own one lower receiver and have access to both 5.56x45mm and .50 Beowulf chamberings in the form of two separate upper receivers.


AR-15 Magazines

While both 5.56x45mm and .50 Beowulf chambered AR-15s utilize the same receiver sets, they also can make use of the same magazines. While you can load .50 Beowulf rounds into a standard AR-15 magazine designated for 5.56x45mm ammunition, you will experience a reduction in capacity.

There are specific magazines manufactured for .50 Beowulf by different manufacturers such as Alexander Arms and C Products Defense.

PMC 5.56 55 gr FMJ
PMC 5.56 55grain FMJ

Projectile and Case Size

An immediate difference between the 5.56x45mm and .50 Beowulf are the size of the projectile and casings. The 5.56x45mm’s parent case is the .223 Remington while the .50 Beowulf is derived from the .50 Action Express. Obviously, one cannot utilize casings from one round to reload the other. Your average 5.56x45mm cartridges will often feature a 55 grain or 62 grain projectile with other options.

.50 Beowulf ammunition will feature a considerably heavier projectile, often ranging from 300 grain to 420 grain options. The diameter of the projectiles is also considerably different. Metrically, .50 Beowulf equates to 12.7x42mm, making the projectiles twice as large as the projectile found in 5.56x45mm cartridges.



The 5.56x45mm cartridge is going to be the much more commercially available round when compared to the 50 Beowulf. The ammunition pool for your 5.56x45mm chambered AR is going to be even more extensive due to the fact that .223 Remington can also be fired in firearms with this chambering. Common loadings for the 5.56x45mm cartridge include offerings in military specifications such as 55 grain M193 and 62 grain M855.

While the .50 Beowulf cartridge is exotic in nature and not as mainstream as the 5.56x45mm, there are still multiple loadings available for those who wish to shoot the cartridge. Alexander Arms and Underwood Ammo provide a variety of loads that afford .50 Beowulf shooters with multiple options such as jacketed hollow point and lead-free projectiles.



Both the 5.56x45mm and the .50 Beowulf are good options for target shooting and plinking, though the former is typically more affordable to shoot than the latter. The two cartridges have been utilized in hunting applications. The 5.56x45mm excels particularly well in the realms of small game and varmint hunting while the .50 Beowulf can more humanely dispatch larger game.



At the end of the day, both 5.56x45mm and .50 Beowulf will serve a variety of shooters well. In the grand scheme of things, you don’t actually have to pick one cartridge over the other as you can easily swap an upper if you wanted to shoot a different caliber. You can easily buy an upper to accommodate one or both of these calibers in addition to any of the other chamberings available for an AR-15.

At the end of the day, choose the calibers you feel work the best for your use cases and be sure to practice with what you end up going with. We here at True Shot Academy want everyone to be the best shooter they can be and will happily assist you in your ammunition procurement needs. Happy shooting.


Need bulk ammo? At True Shot Ammo, we have a wide variety of handgun ammo and rifle ammo available to purchase. Please visit our website trueshotammo.com, call us at (888) 736-6587, or you can email us at [email protected] for more ammo options.

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