New Cartridge Developments and Implications for Dismounted Infantry Soldiers

[JASmith]

...With caseless ammunition why would we be subjected to a 115gr limit?

Good point!

Also, a couple of earlier posts observed good velocities.

The added velocity is not necessarily a result of greater pressure or improved burn profiles even though I think the latter is indeed a factor.

I remember seeing the hype about how the ultra fat cartridges had better velocities for the same pressures as their full-length forebears. A little work with QuickLoad shows that the velocity enhancement in those cartridges is completely explained by the longer bullet travel for the same nominal barrel length. A shorter cartridge means that the bullet base starts out closer to the breech face, so it has to go further for a barrel whose length is defined as the distance from the breech face to the muzzle.

That difference could explain part of the velocity increase with telescoped ammunition.