.280 Enfield...Ahead of its time

[stanc]

For the MRMG (Multi-Role Machine-Gun) load, there is plenty of room to play with for weight in the high sectional density of 6.5mm projectiles without magwell restrictions.

What does that mean? Have you revised your MRMG (I still think Optimized Machine Gun makes a better acronym. :p ) concept to use bullets lighter than 120 grains?

Here's an extreme example of a very long Japanese 6.5mm projectile:

:confused: It's not unusually long for caliber. L/D is ~5.0, about the same as for 6.5 Swede 140-144gr, lead-core, FMJ bullets.

Military 130-140gr "green" and steel-core ball projectiles would have L/D in the 5.6-6.2 range. That might raise issues with rifling twist, terminal performance at <200 meters, and torsion effects of the long-loaded bullets in machine gun links.