Since the introduction of 6.5 Grendel in 2003, we have been in an era of new High Performance Intermediate Cartridges, primarily driven by delivering the most performance possible from within the AR-15 receiver set, while still bringing double-stack staggered capacity magazines.
The demand for this performance is driven by both the private and military sectors with a lot of overlap in requirements. Those of us who got into AR-10s and SR-25s early-on became quickly familiar with the weight, bulk, and sight picture disturbance penalties paid with .308 and similar cartridges that fit into that form factor, so became a bit disillusioned with the large frame guns.
Since 2003, we have seen several cartridges introduced to work from within the AR-15 to deliver more energy on-target, while keeping recoil and sight picture under control. Here is a list of most of them that double-stack and have/had solid company support.
6.5 Grendel
6.8 SPC
300 Whisper/300 BLK
6mm Hagar
.25-45 Sharps
6mm AR (Grendel necked down)
224 AR (Grendel necked down to .224”)
7.62x40 WT
224 Valkyrie
24 Nosler
22 Nosler
6mm ARC (Grendel with shoulder moved back .030” necked down)
350 Legend
300 HAM'R
6mm Max
22 ARC (22 AR formalized by Hornady)
So we have 1x 6.5mm, 1x .277”/6.8mm, 3x .30 Cal/7.62mm, 5x .243”/6mm, 1x .257”, 4x .224”, and 1x .357”.
For 6.5 Grendel, we have bullet weights ranging from 80-160gr, with 124 factory options covering 85-140gr.
For 6.8, there are bullet weights ranging from 85-140gr, factory ammo 87.5-120gr. Almost all of it is 110gr or 115gr though.
For .30 cal, there are bullet weights of 110gr-220gr (subsonic 300 Whisper/BLK use heavier, supersonic use 110gr-125gr). 300 HAM’R uses 110-150gr.
For 6mm, bullet weights range from 55-110gr. The Grendel-based 6mm cases can use the full range of 6mm bullets. The longer cases were limited to 55-75gr, 55-90gr, or 55-100gr.
For all the bottleneck supersonic cartridges, the average bullet weight is 97.5gr with rough calculations.
Most of the above cartridges are dead or on the verge of dying. 6mm Hagar is dead, as is 25-45 Sharps and 7.62x40 WT (replaced by 300 HAM’R). 224 Valkyrie has some degree of following with Federal keeping ammo prices low to try to save it, but it doesn’t offer much over 5.56 when you look at 62-75gr velocities. 24 Nosler and 22 Nosler are all but dead. 6mm ARC and 22 ARC will put the final nails in their coffins I think.
That leaves us with 6.5 Grendel, 6.8 SPC, 300 BLK, 6mm ARC, 6mm Max, and 22 ARC. 350 Legend and 300 HAM’R are for niche hunting applications with a straight wall approach. HAM’R has a shoulder but it’s effectively a straight wall.
When I’ve compared the Grendel against the 6mms, I’m seeing a lot of overlap due to faster mv from Grendel due to piston area/bore volume. Doppler Radar data seems to indicate we’ve been misled with BCs again for many of the 6mm bullets, so my 100-110gr 6.5mm real-world trajectories have matched or exceeded the 6mms of the same weights. 18” Grendel seems to match 24” 6mm AR and ARC with 90-107gr weights, with a bit less chamber pressure as well.
6.5 Grendel continues to remain the most capable and versatile alternate chambering for the AR-15, with a ton of factory ammo support.
The demand for this performance is driven by both the private and military sectors with a lot of overlap in requirements. Those of us who got into AR-10s and SR-25s early-on became quickly familiar with the weight, bulk, and sight picture disturbance penalties paid with .308 and similar cartridges that fit into that form factor, so became a bit disillusioned with the large frame guns.
Since 2003, we have seen several cartridges introduced to work from within the AR-15 to deliver more energy on-target, while keeping recoil and sight picture under control. Here is a list of most of them that double-stack and have/had solid company support.
6.5 Grendel
6.8 SPC
300 Whisper/300 BLK
6mm Hagar
.25-45 Sharps
6mm AR (Grendel necked down)
224 AR (Grendel necked down to .224”)
7.62x40 WT
224 Valkyrie
24 Nosler
22 Nosler
6mm ARC (Grendel with shoulder moved back .030” necked down)
350 Legend
300 HAM'R
6mm Max
22 ARC (22 AR formalized by Hornady)
So we have 1x 6.5mm, 1x .277”/6.8mm, 3x .30 Cal/7.62mm, 5x .243”/6mm, 1x .257”, 4x .224”, and 1x .357”.
For 6.5 Grendel, we have bullet weights ranging from 80-160gr, with 124 factory options covering 85-140gr.
For 6.8, there are bullet weights ranging from 85-140gr, factory ammo 87.5-120gr. Almost all of it is 110gr or 115gr though.
For .30 cal, there are bullet weights of 110gr-220gr (subsonic 300 Whisper/BLK use heavier, supersonic use 110gr-125gr). 300 HAM’R uses 110-150gr.
For 6mm, bullet weights range from 55-110gr. The Grendel-based 6mm cases can use the full range of 6mm bullets. The longer cases were limited to 55-75gr, 55-90gr, or 55-100gr.
For all the bottleneck supersonic cartridges, the average bullet weight is 97.5gr with rough calculations.
Most of the above cartridges are dead or on the verge of dying. 6mm Hagar is dead, as is 25-45 Sharps and 7.62x40 WT (replaced by 300 HAM’R). 224 Valkyrie has some degree of following with Federal keeping ammo prices low to try to save it, but it doesn’t offer much over 5.56 when you look at 62-75gr velocities. 24 Nosler and 22 Nosler are all but dead. 6mm ARC and 22 ARC will put the final nails in their coffins I think.
That leaves us with 6.5 Grendel, 6.8 SPC, 300 BLK, 6mm ARC, 6mm Max, and 22 ARC. 350 Legend and 300 HAM’R are for niche hunting applications with a straight wall approach. HAM’R has a shoulder but it’s effectively a straight wall.
When I’ve compared the Grendel against the 6mms, I’m seeing a lot of overlap due to faster mv from Grendel due to piston area/bore volume. Doppler Radar data seems to indicate we’ve been misled with BCs again for many of the 6mm bullets, so my 100-110gr 6.5mm real-world trajectories have matched or exceeded the 6mms of the same weights. 18” Grendel seems to match 24” 6mm AR and ARC with 90-107gr weights, with a bit less chamber pressure as well.
6.5 Grendel continues to remain the most capable and versatile alternate chambering for the AR-15, with a ton of factory ammo support.
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