Originally Posted by J E Custom
The Grendel was designed for the AR15 frame and will work in the standard action.
The 100 grain loading is very slow (2370 ft/sec) the 6mm WSSM
has a lot more case capacity and will push the 100 grain to 3110 ft/sec
So there is not much to compare. The WSSM has a huge advantage over the 6.5 Grendel
but normally you have to use a AR 10 for the WSSM.
The Grendel is a great cartrige in an AR and is more powerful than the standard 223.
The 6mm has slightly better ballistics than the 6.5 with the same weight bullets.
J E CUSTOM
JE I'm not sure where you are getting your data on the Grendel but it sure is way off from pretty much everything I've seen published on it.
From Chuck Hawks site
Here are some hunting reloads developed by David M. Fortier and first published in Shooting Times
Magazine. Mr. Fortier used Lapua brass and Federal Gold Medal Small Rifle Match primers for all loads:
Hornady 100 grain SP bullet, 30.0 grains Western Powder X-Terminator, COL 2.25", MV 2807 fps.
Hornady 100 grain SP bullet, 30.5 grains Western Powder X-Terminator, COL 2.25", MV 2846 fps.
Nosler 120 grain Ballistic Tip bullet, 31.0 grains AA2520 powder, COL 2.26", MV 2636 fps.
Nosler 120 grain Ballistic Tip bullet, 29.0 grains RL-15 powder, COL 2.26", MV 2526 fps.
ad Development and 1000-yard Performance
Arne tells us: "Having shot thousands of rounds in developing the 6.5 Grendel cartridge (and in testing 6.5 PPCs), we had a good idea of what would work in the bolt gun--Vihtavuori N530 and Western TAC. Both these powders have load densities, kernel sizes, and burn rates that work well with the Grendel case. Though we're still early in the load development process for the F-Classer, our load of Vihtavuori N530 with Fed 205M primers and moly'd JLK 130s produces consistent 2760 fps velocities from a 28" barrel. This load is grouping well, even though it took some time for us to get used to that 2-ounce Jewell trigger! (To an AR15 shooter, one pound is a "light" trigger pull). The N530 and JLK 130gr VLD load produced 6"-7" witnessed five-shot groups at 1,000 yards. The amount of drop at 1000 yards surprised us--an even 30 MOA of adjustment (from a 100-yard zero) got us on target at 1000. That's nearly dead-even with a 6BR shooting a 107gr Sierra MK at 2900 fps. That means, at very long-range, the superior BC of the 6.5mm JLK made up for the lower initial velocity of the Grendel.
How the 6.5 Grendel Stacks Up Ballistically
With the great performance of the 6BR, and the availability of larger 6.5mm cartridges such as the Rem 260 (6.5-08), one can ask "what is the advantage of the 6.5 Grendel"? The answer is three-fold: size (form factor), efficiency, and BC. The Grendel will fit in an AR15 platform. The Rem 260 will not. The Grendel can push a 130gr bullet to 2760 fps with 15 grains less powder than a Rem 260. Burning less powder reduces recoil, and signficantly extends barrel life.
Compared to a 6BR, the 6.5 Grendel enjoys the advantage of shooting higher BC bullets. For example, the 6.5mm Lapua Scenar 123gr bullet, with its .542 BC, beats the .530 BC 6mm 107gr Sierra Match-King. And the new 6.5mm 130gr JLK bullets enjoy a BC advantage over ANY 6mm projectile available, even the DTAC 115gr. Initial tests of the 130gr JLK show a BC of .620, which beats the DTAC, with its BC of approximately .580. The larger bore diameter of the 6.5 Grendel allows it to drive a heavier bullet at lower pressures. The same principle applies to the 30BR, one of the most efficient cartridges ever.