The 375 Remington Ultra Magnum, or 375 RUM, seems capable of respectable ELR ballistics.

This is not apparent from the available powder data, as the cartridge is known to be a big bore hunting cartridge, not a cartridge for ELR.

The availability of high BC monolithics extend the envelope of possibility.

With a 0.48 G1 BC at 3200 fps, the trajectory chart looks like this for sea level air pressure :

With a 0.69 G1 BC at 3000 fps, the trajectory chart looks even better :

This data suggests that with a 300 MOA adjustable base, two miles is possible.

This is what the 247 grain and 300 grain bullets in these charts look like :