The discussion opens with a comparison between the 7.62x39 cartridge and 6.5 Grendel. 7.62x39 is described as a long-established, widely produced cartridge that is enjoyable to shoot and strongly associated with “commie guns” and AK platforms. In contrast, 6.5 Grendel is presented as a newer, “spicy” option for the AR-15 platform. One speaker notes having built an AR-15 upper in 6.5 Grendel and calls it a favorite AR-15 caliber compared with 5.56 and 7.62x39. The hosts liken 6.5 Grendel to a smaller 6.5 Creedmoor in concept, offering similar ballistic characteristics in the AR-15 that 6.5 Creedmoor brings to the AR-10, but within a lighter, smaller receiver and component set.
The hosts move to range impressions using an AK pistol in 7.62x39 and an AR-15 style pistol in 6.5 Grendel. The Century Arms VSKA AK pistol in 7.62x39 is noted for its aggressive muzzle brake, short barrel, and visible fireballs, yet recoil is described as easy to manage and enjoyable. The 7.62x39 round is characterized as never being particularly difficult to shoot, even in pistol-length AK configurations. When switching to the 6.5 Grendel AR pistol, the recoil feels very similar despite the different operating systems: long-stroke gas piston on the AK and direct impingement on the AR. The shooters describe the recoil impulses as close enough that it is hard to distinguish a significant difference between the two pistols.
Back from the range, the conversation turns to how each cartridge performs from short barrels. The similar felt recoil between the pistols is partly attributed to the VSKA’s muzzle brake and the 6.5 Grendel pistol lacking any muzzle device. When considering effectiveness from comparable barrel lengths, the hosts highlight that 7.62x39 commercial ammunition is typically very consistent in bullet weight, usually around 122 to 124 grains with little variation. In contrast, 6.5 Grendel offers a broader range of commercially available bullet weights, from about 90 grains up to roughly 130 grains. This variety allows different loadings for different purposes while using a similar case capacity, pushing lighter or similarly weighted projectiles at higher speeds from compact platforms.
The discussion then focuses on ballistic characteristics. The 6.5 Grendel projectile is described as thin and long, with a higher ballistic coefficient than the wider 7.62x39 bullet. This shape helps 6.5 Grendel resist wind and retain energy better over distance, while the larger-diameter 7.62x39 projectile tends to shed energy more quickly. When comparing similar bullet weights, such as a 120-grain 6.5 Grendel load versus a 122-grain 7.62x39 load, 6.5 Grendel is said to produce roughly several hundred feet per second more velocity and around 100 to 200 additional foot-pounds of energy. Approximate figures mentioned include about 2,300 feet per second for typical 7.62x39 loads versus around 2,600 feet per second for comparable 6.5 Grendel loads, illustrating the performance advantage from the same general cartridge envelope.
The hosts acknowledge that the comparison is somewhat uneven because 7.62x39 has been in service since the late 1940s, while 6.5 Grendel is a much more recent design. 6.5 Grendel was developed by Bill Alexander of Alexander Arms as a high-performance AR-15 cartridge. It traces its lineage through earlier cases such as the 6.5 PPC and 220 Russian, sharing a common family tree while being optimized for modern performance. The point is made that decades of technological advancement and focused engineering should yield a better-performing round within the AR-15’s constraints, and the hosts agree that 6.5 Grendel achieves this without implying any inherent flaw in 7.62x39. One host still expresses a preference for the “slow and fat” character of 7.62x39, emphasizing that both cartridges have valid roles.
The conversation closes by examining design trade-offs in the AR-15 platform. Cartridge designers must balance power, recoil, firearm size, and magazine capacity. Larger, more powerful rounds can be created, such as the .50 Beowulf from Alexander Arms, but these often require single-stack magazines and reduced capacity. With 6.5 Grendel, a standard 30-round 5.56 magazine capacity typically becomes about 26 rounds, a modest reduction. In return, users gain higher velocity and energy, especially with projectiles around 120 to 123 grains that can be driven roughly 300 feet per second faster and with about 200 extra foot-pounds of energy compared to similar-weight 5.56 or 7.62x39 loads. The hosts conclude that 6.5 Grendel is a strong performer in the AR-15, while 7.62x39 remains a soft-recoiling, familiar option, particularly for shooters experienced with AK platforms.