A Complete Guide to 6.5 Grendel vs. 5.56 NATO

Posted by Faxon Firearms Staff on Feb 9th 2023

A Complete Guide to 6.5 Grendel vs. 5.56 NATO

If you are wondering which is better between the 6.5 Grendel vs 5.56 NATO, a lot of the answer comes down to how you plan to use the gun. Key differences include:

- Bullet Weight and Size

- Performance

- Magazine capacity

- Real-World Usage

The short of it is that the 6.5 Grendel rifle has a longer barrel that has greater energy, and with the 5.56 NATO the bullets fly faster. Those two facts help to set up the comparison between two very capable rounds and where the debate over the 6.5 Grendel or the 5.56 NATO begins.

As AR-15 options, both guns perform somewhat differently but still remain true to the AR platform. Much of this discussion will revolve around the bullets and performance, but also take in some options for add-ons.


6.5 Grendel weight - ranges from 90 grain to 130 grain with three options in the middle.

5.56 NATO weight - ranges from 55 grain (ball rounds) to 62 and 63 grain NATO rounds.

The 6.5 Grendel is a heavier bullet; the physical weight ranges from 14.7 to 17.8 grams. Originally, the 6.5 Grendel round was an answer to a question that addressed the need for greater accuracy at longer distances in the AR-15 arena. Primarily, this was the need for competitive shooters. The desperation for longer range headed away from the semi-automatic rifles and into bolt action single round 90-grain VLD rounds.

What the 6.5 Grendel does is it brings the semi-automatic option back into distance shooting with an AR-15 platform. You have options for both a Grendel upper and lower receiver. The effective range for the 6.5 Grendel is around the 800-yard mark, and possibly up to the 1,000-yard mark. The difference between 800 yards and 1,000 yards comes down to the quality of the gun's parts and the shooter's skill.

With the 5.56 NATO, you are looking at 650 yards and nearer before accuracy drops significantly. That means that the 5.56 NATO offers excellent short-range accuracy, and the 6.5 Grendel offers long-range accuracy.


The 6.5 Grendel is slightly fatter than the 5.56 NATO round which is one of the key factors in how each round performs. The larger bullet diameter of the 6.5 Grendel is one of the reasons it delivers greater power over distance. Bullet type will also have an "impact" on accuracy depending on the distance.

6.5 Grendel bullet- Overall length - 2.26 inches long - case = 1.52 inches - Base Diameter = .439 inches

5.56 NATO bullet - Overall length 2.26 inches long - case = 1.76 inches - Base Diameter = .377 inches

The differences in size come with various bullet types, casing materials, and diameters given to each AR-15 model.


6.5 Grendel - 90 grain - 2,880 feet/second - 1,658 ft-lbf

6.5 Grendel - 130 grain Norma - 2,510 feet/second - 1,818 ft-lbf

5.56 x 45mm NATO - 55 grain - 3,260 feet/second - 1,294 ft-lbf

5.56 x 45 NATO - 63 grain (GP 90 FMJBT) - 2,790 feet/second - 1,238 ft-lbf

We've taken the lowest grain and the highest grain of each round - Grendel and 5.56 NATO - to illustrate the breadth of performance for each. What you see, is that the 5.56 NATO is faster by a lot with lighter bullets and that the 6.5 Grendel packs more punch with much higher energy and impact.

Magazine Capacity and Bullets

Many questions revolve around the number of rounds that a magazine for the 6.5 Grendel and the 5.56 NATO rounds. One important piece of information is that you can use the 6.5 Grendel round in a 5.56 NATO magazine, but you will only be able to carry a few rounds because of the size difference between the two.

You can carry between 24-26 rounds of 6.5 Grendel in aftermarket magazines such as the 30-round Heckler & Koch magazine or 24 rounds in an E-Lander 6.5 Grendel magazine.

Several magazines offer a 30-round capacity for 5.56 NATO.

You also have options for smaller amounts such as 5-round mags or intermediate cartridge options in the 10, 20, and 28 round capacities for 5.56 NATO rounds.Real-World Uses

6.5 Grendel Hunting - is an excellent hunting option for both the round and the gun. The best features are its small recoil and outstanding stats. With a longer accuracy than the 5.56 NATO, you don't have to get as close with the 6.5 Grendel. That fact makes it ideal for those who hunt deer and game that are deer-sized, such as goats or antelope. With wild game bigger than deer, it is better to go up to a .308 option, especially for big game such as elk, moose, and bear.

Home Defense - If you are looking for a cartridge that is best suited for home defense, the 5.56 NATO is a better option than the 6.5 Grendel. The 5.56 NATO is faster to the target thanks to its shorter barrel length, and also offers less recoil which helps keep more rounds flying in the general area of the target. Technically, you could manage the 6.5 Grendel for home defense; it would just not be the most ideal option. The 5.56 NATO offers less over-penetration in home defense situations.

5.56 NATO - Hunting - The 5.56 NATO is a good round for hunting but not necessarily for hunting deer or larger game. The round offers amazing speed from gun to target, but not at great distances. If you hunt, use the 5.56 NATO for smaller wild game such as feral hogs or varmint hunting.

Which is better the 6.5 Grendel or the 5.56 NATO?

Better is always a perspective and often based on outcomes or goals, so there is no clear winner. If you want an AR-15 with better long-range shooting, then you will find the 6.5 Grendel to be the better choice over the 5.56 NATO. If you are looking for an AR-15 gun for big game animals, you will likely find that neither option is the best. In a big game hunt, you want a round that offers more impact and greater penetration with significant damage.

If you are in a rural area where your property is plagued by wild pigs and coyotes, then either option is going to work well for you. If you can get within 650 feet of your target, go for the 5.56 NATO. If the targets are more skittish, and it is difficult to get within 650 feet of them, the 6.5 Grendel is a good option.

Faxon’s 6.5 Grendel and .233 Wylde Barrels and Accessories

A sampling of options from Faxon include:

Barrels - One of the most customized pieces of AR-15 firearms is the barrels. Faxon offers 6.5 Grendel barrels and extensions in 12, 16, 18, and 20-inch units with various high-quality finishes. For 5.56 NATO barrels and extensions, Faxon offers them in 7.5, 10.5, 11.5, 14.5, 16, 18, and 20-inch units manufactured with 4150 stainless steel

Uppers - Customize your AR-15 with options for upper receivers including their 10.5 5.56 barreled upper receiver or the ARAK-21 5.56 upper receiver with a barrel assembly unit with an option to add a second. Installation takes less than a minute

Faxon offers quality manufacturing of AR-15 parts and accessories. All parts and add-ons are manufactured 100 percent in-house with exacting quality control checks and highly engineered processes that result in unique products and add-ons that increase the value of your AR and the experience of shooting it.

Be sure to shop the large range of cartridges that Faxon offers for both the 6.5 Grendel and the 5.56 NATO platforms.

Quality Lab In-house to Check Quality

Faxon focuses on the finer details and our in-house quality lab and team test each part to ensure it meets standards including machining standards, metal quality standards, and finishing standards so that each customer is delighted with their purchase. The goal is always to exceed expectations while adhering to industry standards including the process of designing new parts or add-ons.

Metal Testing

Faxon Metal Testing - because of the high power and stress that metal pieces undergo during the round firing process, Faxon tests all metal parts using a Magnetic particle engaging process that tests for metal fatigue and stress that can occur during the smelting and casting process. The result is solid, reliable metal parts that can stand up to the regular use of your AR rifle.

Finish Lab - All customized finishes are inspected for uniform coloring, flaws, and other issues that may cause the coating to diminish over time. The Faxon Better Coating process enables the application of unique finishes and coatings with exacting standards.

As a family-owned and operated firearms outlet, the quality of Faxon is duly noted by past customers. Read through the long list of customer reviews on each product that highlight the accuracy, types of Ammo, OEM-grade parts, and unique accessories for the guns we service.