just use the data for the 75 Hornady HPBT bullet or Sierra 77. The A-max has a little less bearing surface than those two bullets and you will need to seat them out longer than 2.260 for them to work properly, so the pressure will be lower with that data.
Are you loading for the .223? If so , it's in Hornady's 7th addition. It lists 19.4 to 23.5 of Varget. Velocity from a 20" AR with 1 in 9 twist is listed as 2200 to 2600 fps.