......The Ultimate Muzzleloader sets a new performance threshold with the use of a closed breech system that provides a cleaner and hotter ignition. The UML ignition system uses a uniquely-sized brass case with a Remington 9 ˝ large magnum rifle primer that is push fed into the breech plug creating a gas seal in the flash hole of the primer (see cutaway below). The result allows the shooter to load up to 200 grains of powder for increased range, energy, and on-game performance.
Using 200 grains of Triple Seven® Pellets in combination with Barnes’ Spit-Fire T-EZTM 250-grain muzzleloader bullets, the Model 700 Ultimate Muzzleloader gives the shooter the ability to reach velocities over 2400 fps. With Remington’s patented breech plug technology, shooters can now experience centerfire-like performance and accuracy out of a muzzleloader.
I know it would be more efficient with a closed breach but is it possible to burn that much powder in that length barrel? Even the old black powder rifles weren't using near that, .50-90, .50-110, .45-70 etc.