A lot of info can be found here A-191 Cartridge Development - Press release
Does not give the charge of Re-22 but if memory serves it is around 72 gr (work up to this) with a 190 gr Sierra. The navy is stretching the 300 WIN MAG out to 1500 now using the 220 gr Sierra as a less costly change than going to the 338 Lapua.
I've not done enough research on the propellant to even give an educated guess.
Several years ago I shot a 500 yard Match with a guy shooting the Black Hills version of the A191 and it shot very well at 500 yards.
Hope this helps.