Optimum 6.5 Grendel bullet weights

[stanc]

If we assume the military is going to want an M855A1 type bullet with a copper core and steel penetrator, then the length can be preserved as compared to a lead core bullet without voids.

We know that the Grendel starts to lose energy at above 120 grains or so grains of bullet weight because of powder, length, and pressure limits of the cartridge.

Since those factors are trade offs, plotted lines of Energy and BC on a graph as the bullet weight decreases would cross at some bullet weight. That would be the optimum, and it looks like that point is at about 110-115 grains.

Interesting. Thanks!

If we look at designs with the steel penetrator tips, in addition to making the bullet longer, the steel tip is lighter than the copper/zinc alloys used in gilding metal. That shifts the center of gravity to the rear, which makes it more likely that the bullet will tumble on impact. That's a good thing for stopping ability.

This is kind of a worst case comparison because I doubt you could make and M855A1 type bullet with a copper core and steel penetrator at a weight of 120-123 grains with a BC matching the Lapua Scenar and not have it so long that it reduces the powder load.

Concur. It looks to me like it'd have to be at least as long as the 120gr GMX, which has a BC much lower than the 123gr Scenar.