12-07-2022, 05:41 PM
From my understanding, Arne Brennan was looking for a 600m+ competition cartridge that would work from an AR15. In an interview, Brennan stated that, at the time, the Lapua Scenar 6.5mm bullets in 123 and 108 grains had the best combination of high BC and bullet length in their class and offered a ballistic advantage to the existing 6mm bullets*. Brennan stated that he had been working on a 6.5mm PPC-based cartridge and it was Lapua that proposed moving the shoulder foreword (sometimes this was called the PPC-X case). FWIW, Even though the 6.5 Grendel was designed for the AR15, Mr. Brennan often competed with a custom bolt action and loaded 108 grain Scenars to very high pressures (he subsequently switched to Lapua's 6.5x47 for bolt-gun work). This article has more details : https://www.accurateshooter.com/guns-of-...by-speedy/
I know less about Bill Alexander's intent for the 6.5 Grendel, but most of the early demonstrations were of the Scenar bullets and more directed towards the military than hunters. The first widespread publicity that I saw about the Grendel was from an exhibition at Blackwater that involved shooting through various barriers using a relatively heavy (144 grain, maybe?) bullet. The Wikipedia page for the 6.5 Grendel gives an idea of how the cartridge was generally viewed early on: more of a military and target cartridge than a hunting one. A great deal of the early data is from 24" barrels rather than the shorter ones generally preferred by hunters. To this day, detractors of the cartridge often incorrectly claim that the Grendel requires a long barrel for reasonable performance, largely because most of the performance claims were from 24" barrels.
*It is important to note that the 6.5mm Lapua Scenars were outliers at the time. It was the combination of high BC and larger diameter that made the 6.5mm PPC and Grendels competitive against 6mm versions. The larger diameter gave an increased swept-bore-volume that allowed slightly more efficient use of the powder charge, according to Brennan. Newer, higher BC 6mm bullets have negated that advantage.
I know less about Bill Alexander's intent for the 6.5 Grendel, but most of the early demonstrations were of the Scenar bullets and more directed towards the military than hunters. The first widespread publicity that I saw about the Grendel was from an exhibition at Blackwater that involved shooting through various barriers using a relatively heavy (144 grain, maybe?) bullet. The Wikipedia page for the 6.5 Grendel gives an idea of how the cartridge was generally viewed early on: more of a military and target cartridge than a hunting one. A great deal of the early data is from 24" barrels rather than the shorter ones generally preferred by hunters. To this day, detractors of the cartridge often incorrectly claim that the Grendel requires a long barrel for reasonable performance, largely because most of the performance claims were from 24" barrels.
*It is important to note that the 6.5mm Lapua Scenars were outliers at the time. It was the combination of high BC and larger diameter that made the 6.5mm PPC and Grendels competitive against 6mm versions. The larger diameter gave an increased swept-bore-volume that allowed slightly more efficient use of the powder charge, according to Brennan. Newer, higher BC 6mm bullets have negated that advantage.