6.5 Grendel vs .243

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In an attempt to find the better of 6.5 Grendel vs .243, I tried out both rounds and conducted an analysis of its user’s feedback. I gathered the few variations between these two rounds, and I must admit that most of these variations all pointed back to one element, which is the design of their body and finishing. The Grendel seems to take on a pointy tip and a more compact build, whereas the 243 features a blunt rounded front end of the bullet.

Not a lot has been said in comparison to the 6.5 Grendel and the 243 Winchester. My guess is because there is not much to be compared between the two most popular AR 15 rounds. Their popularity lies in their premium quality, and consistent performances that have competed even before most of us were conceived. 

For a smooth understanding as to where their differences lie, you will first need to understand the build and characteristics of each. 

6.5 Grendel

The 6.5mm Grendel is an intermediate cartridge that has seen its prevalence in the hunting scene and holds a high reputation. It’s perfectly constructed design is all thanks to a group of engineers led by one Anne Brennan in the Alexander Arms makers. It is a low recoil round that does not compromise its efficiency as it is an extremely accurate and useful AR15 based projectile.

Its body form and shape allow for it to provide spectacular shooting accuracy on long and medium-range attempts. It also means that is extremely reliable and even more lethal on short-range shots. The 6.5 features all the beautiful features from its parent case, the 6.5mm PPC, with additional improvements that sum up to an excellent modern rifle magazine.

Its use in bolt action rifles in the hunting of medium-sized game is a trend that is gaining pace pretty quickly in the United States. On its introduction to the market back in 2003, its primary goal was to maximize the efficiency of AR ammunition between 200-800 yards. As expected, these projectiles delivered what was required of them. 

The size of this round is smaller in comparison to other rifle rounds; this is after the finding that a massive body somehow compromises the efficiency of the projectile. With this knowledge in mind, the designing team set forth to coming up with a shorter and streamlined cartridge. And then was the 6.5 Grendel introduced to the market.

What are the Attributes of the 6.5 Grendel?

Exterior Design

Since its parent case is the .220 Russian, the 6.5 tends to take its design and attributes on after it. Its makers understood that only a few modifications were needed on the already successful projectile to make it even more useful. The casing takes a bottleneck design with a rimless base for quicker expansion once in the target.

It is no lie that this design is what makes the 6.5 more lethal while comparing it to other hunting rounds. Its pointy tip, which measures about 6.7 mm in diameter, allows for maximum penetration with the least amount of force and pressure required. To support the end in piercing through tough animal skins is its 7.44mm neck diameter. 

As we head downwards on the round’s build, a 10.87mm shoulder diameter increases the cartridge’s stability. It is also this measurement that is responsible for the bottleneck design on the rifle rounds. Its base is the widest with a diameter of 11.15mm and an un-noticeable rim of 1.5mm in thickness.

The 6.5 is not a massive projectile, hence its use of small rifle primers covering up the base. Due to its size and build, it is not known to gulp down large volumes of powder as most rifle rounds do. It is with these elements that we get to enjoy the spectacular functioning of this cartridge.

Ballistic Performance

Generally, with the Grendel cartridge, each additional grain in the accommodated bullet weight reduces the muzzle velocity by approximately 10.8fps. This claim was entirely backed by the test results of the 6.5 cartridges.

When loaded with a 108-grain bullet, the projectile breaks at a muzzle velocity of 2700fps. As I tried loading on a more massive grain, 123 grains, the speed was reduced to 2620fps. I also carried out other tests involving different weights, and I can confidently claim that the heavier the bullet, the less its breaking velocity.

From the tests, I also discovered that it is not only the weight that affects the speed, but the barrel length also decides on the breaking velocity. As a basis for your future reference, note that with every inch added to the barrel equals a 20fps increase in the projectile’s muzzle velocity.

.243 Winchester

In firearm production, Winchester is a respected and coveted brand that boasts of a long catalog of world-class creations. At the top of their best sellers lies the .243 Winchester rifle cartridge, which is a favorite to most hunters and competitive long-range shooters. Claims of its use by law enforcement officers in the early years prove just how effective they are.

Initially, this spectacular piece was explicit to varmint hunting; however, with its excellent performance, it found its way to hunting even bigger games. Unlike the 6.5 Grendel, this particular is more massive and can propel and carve its path through strong winds maintaining its velocity reliably. In modern hunting applications, the 243 sees its use in terrorizing coyotes, deer, and even wild hogs.

Its casing nature allows it to accommodate a wide variety of weights from 55-105 grams. As you would expect, bullets weighing less than 90 grams are best for varmints, whereas heavier weights are for the medium-sized game. I advise that you take this information seriously as the right bullet is a necessity for a successful shot attempt.

Since its introduction in the market in 1955, the 243 reputation exceeds almost all AR rifle rounds. It boasts improved elements from its parent case, which is the 308 Winchester case. Its mechanical improvements and design finishing allow for a more accurate and low recoil cartridge that is efficient even on those long-range target practices.

What to Expect From the 243

Ergonomic Design

As stated earlier in this article, this cartridge is mostly used in the hunting scene. It thrives in this genre mainly because its design and body build allows it to accommodate a variety of bullet grains. Just like the Grendel, lighter rounds are more efficient on the smaller game and vice versa.

This spectacular cartridge is a proud product from Winchester manufacturers, and its make is almost similar to its parent case. It is an improved and advanced version of the previous models and has a modern layout and finishing.

Its upper build comprises a 6.22mm bullet diameter followed by a slightly wider neck of 7mm and shoulders measuring 11.5mm. From a simple observation of these figures, you can picture the trend, as it widens as you move downwards. The slimmer tip maximizes penetration while the broader elements help it maintain inflight velocity and accuracy.

With a base diameter of 12mm, this cartridge is known to swallow up chunks of gunpowder. As some view this as a downside, it is an advantage as the powder reciprocates to its excellent potency.

Ballistic Performance

With a 100-grain bullet, the cartridge attains a maximum velocity of 2960fps from a 24-inch barrel. As it is capable of accommodating various bullet weights, expect a decrease in the speed with more massive options. Also, a longer barrel length will increase your muzzle velocity by a significant margin.

To sufficiently stabilize the 100-grain bullet, a twist rate of 1:10 is necessary for your weapon of use. Heavier bullets will exit the barrel at a slower pace; hence the need for a lesser twist rate, let’s say 1:8. The tremendous velocity you can attain from these rounds is from the lightest grain, 55 grain, and is 4058fps. However, since it is too light, it will shed off energy and velocity faster.

Why Choose 243 over 6.5 Grendel?

Higher Velocity

Before further analysis, it is crucial to consider the fact the two cartridges house different bullet ranges, making them not an ideal pair to compare. If we decide to base our speed comparison, obviously, the rounds that house the lightest option will win. Because of this, our speed comparison will be based on their designs rather than their bullet weights.

The 243 having a blunt front end, you would expect it to be slower than the pointy 6.5 front tip. However, its body build allows for a larger volume of powder, which boosts its muzzle velocity significantly. Although both cartridges recorded high speeds, there is a slight difference that sees the Grendel lose.

Another disadvantage associated with the Grendel is its quick loss of energy and velocity. Its tip plays a massive role while in flight, but its body build is not heavy enough to maintain life. As a result, you will find that on long-range attempts, the projectile loses almost half its muzzle energy. Unlike the 6.5, the 243s weight helps it hang onto its initial muzzle velocity with minimal shedding.

Considerable Recoil

Concerning the recoil felt on these cartridges, the Grendel results in the lightest kick of the two. In fact, most shooters claim to use this round as introductory ammunition on children to the rifle hunting scene. It may seem as though the 6.5 is better than its counterpart; however, I see this as a small price to pay.

The recoil impact on the 243 is not that massive that a thick stock might not handle. By adding on a detailed buttstock, then you can control this impact and get a conducive shooting experience with the Winchester quality.


Depending on which angle of approach you take, each of the two can be the cheaper option. On one hand, the 243 comes at a pocket-friendly price while the Grendel has an exaggerated price tag. The reason I claim the price exaggerated is that the two fit the same profile, yet one is available at higher pricing.

On the other hand, the running cost of the 243 is greater than that of the Grendel. The 243’s build gobbles up large volumes of powder over its counterpart. From this angle, we conclude that in the long run, the 6.5 will be cheaper.


From the outlined facts to results from different tests, all of us can conclude that both cartridges are excellent purchases. With the right bullet choice, you can use them efficiently in whichever application, be it sporting to hunting.

Personal preference yet again prevails in this comparison, and the final decision is all yours. Personally, the 243 will always remain a favorite. However, everyone is entitled to an opinion, and until you get to try both of them, will you pick your best one.

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