12-06-2011, 10:41 PM
If you are designing a new chamber and rifle, then the bolt thrust issue is a moot point, you can run whatever pressure you designate as the ideal, and build the bolt assembly to match. The longer, skinnier 6.8 case requires a longer extraction movement, with the attendent larger recipricating issues, which creates at least as big a disadvantage as does the ability to make links work for the shorter, fatter case. We know that full auto is no issue with the Grendel because its been run that way in AR's by plenty of people with no complaints.
Heavier doesn't necessarily equal better penetration. At equal velocities, penetration also is affected by frontal area, so a bigger bullet that is heavier might have the same penetration as a lighter, but higher sectional density bullet. (Thats why elephant hunters shot 6.5's instead of bigger bullets, at least some of the time.)
And once again, using same weight bullets, the Grendel has a higher SD, and thus will penetrate better. With a lighter bullet with the same SD, it will also have less recoil, which is another factor in its favor.
Recent development has pretty conclusively shown that short powder columns are more efficient than long powder columns, as well.
BUT....we are arguing about this just to argue, because all of it is theoretical.
Where is JMB when you need him?
Heavier doesn't necessarily equal better penetration. At equal velocities, penetration also is affected by frontal area, so a bigger bullet that is heavier might have the same penetration as a lighter, but higher sectional density bullet. (Thats why elephant hunters shot 6.5's instead of bigger bullets, at least some of the time.)
And once again, using same weight bullets, the Grendel has a higher SD, and thus will penetrate better. With a lighter bullet with the same SD, it will also have less recoil, which is another factor in its favor.
Recent development has pretty conclusively shown that short powder columns are more efficient than long powder columns, as well.
BUT....we are arguing about this just to argue, because all of it is theoretical.
Where is JMB when you need him?
You seek escape from pain. We seek the achievement of happiness. You exist for the sake of avoiding punishment. We exist for the sake of earning rewards. Threats will not make us function; fear is not our incentive. It is not death that we wish to avoid, but life that we wish to live. - John Galt