Beginners Guide to AR15 Calibers

A new shooter has the option to buy a complete AR15 outright, or completely customize their rifle from the ground up to meet their exact wants, needs, and specifications. There are nearly limitless accessories and different parts and components to choose from. But one of the most important aspects, short of the actual rifle itself, is the choice of ammunition to keep loaded and ready to go.

Caliber Options for the AR15

There seems to be an ever-growing list of available calibers for the AR15. Some range from tiny plinking rounds, all the way up to .50 caliber sized rounds. Here is just a short list of some of the available AR15 rifle calibers, and this does not include the equally expansive list of AR10 rifle caliber options:

  • .22LR
  • .223 Rem
  • .224 Valkyrie
  • 5.56x45mm NATO
  • 6.5 Grendel
  • 6.8 SPC
  • .300 BLK
  • 7.62x39mm
  • .350 Legend
  • .450 Bushmaster
  • .458 SOCOM
  • .50 Beowulf

5.56x45mm Options for the AR15

Without deviating into the other calibers available for the AR15, the 5.56x45mm or 5.56 NATO round is ultimately the most popular and most common chambering for the AR15 rifle. As the round designation states, the 5.56mm is the standard round for all NATO countries, hence the wide popularity and availability (under normal circumstances) of ammunition available on the market today. It can be found in different weights ranging from 45 grain varmint hunting rounds, all the way up to 90 grain rounds.

It is important to note, albeit a bit confusing at first, but the standard AR15 rifle round actually can have three different designations. You will most assuredly see either of the three rounds listed as both ammunition options as well as barrel options. These are .223 Remington, .223 Wylde, and the 5.56 NATO round designation. The .223 Remington is actually a bit smaller than the other two. But the general rule is that any barrel marked as a .223 Wylde or 5.56 NATO will be able to shoot all three rounds. But any barrel marked explicitly as .223 Remington should ONLY fire .223 Remington. This is due to the higher pressures created by the .223 Wylde and 5.56 NATO rounds when fired.

Brass Case & Steel Case Ammo Options

AR15 5.56 NATO ammunition can be found in either steel cased or brass cased ammo. Both options have their pros and cons. Brass cased ammo is the ideal casing to use in the AR15. With brass casings, you will extend the life of your barrel over the use of steel cased. Brass is a softer metal than steel, so the wear and tear on inner parts of the AR15 like the chamber and extractor will be less over time and use. Because of the softer makeup of brass, when fired the casing does a better job of expanding, thereby making it easier to extract from the rifle after firing. With steel casings, it does not expand in the way brass does so it requires more gas pressure to extract the round and that increased gas pressure causes undue stress on the extractor itself. The biggest benefit of using steel cased ammo over brass cased is the price. Steel is much cheaper to buy. In some cases, it can be around half the cost to shoot a box of steel cased ammo over brass cased. Over time, the barrel will wear quicker, but the cost savings actually lean more in favor of shooting steel and replacing the barrel than just buying brass cased ammo for the life of the barrel. But the major difference between the two is that brass cased ammo is much more reliable in terms of accuracy and malfunction rates.

Different Types of 5.56 NATO Rounds

There are a couple different options available for the 5.56 NATO round, and each have their own purpose. The most common round available is always going to be full metal jacket rounds, or FMJ. It will be these types of rounds that are best for target shooting. They are the cheapest types of ammunition available and most produced by ammunition manufacturers. When moving into the more specialized defense type ammo or hunting ammo, there is hollow point/jacketed hollow point or soft tip ammunition. These rounds are more expensive to produce and thus more expensive to buy. But in terms of performance, these rounds are what should be trusted when using an AR15 for more than just target shooting.

Because of the near limitless options available for the AR15 platform, your ammunition choices are just as plentiful. You can definitely find ammunition to suit your intended purpose, whether that be target shooting, hunting, longer range precision shooting, and others. Gunspot has plenty of choices for your next AR15 rifle so you can be sure that you will be able to find exactly what you need to successfully take down that steel target or that pesky coyote.

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