I have never seen a 223 Rem. with a 50gr. bullet do much better than 3300fps safely. I always cross reference two or more manuels to check for new loads. If they don' t have the exact data for the load you want sometimes it is close enough to let you know if one of the manuels have bad data which happens from time to time. If you want that kind of performance you will need to use a 22-250 or possible convert your rifle to a 223 Ackley Improved. That doesn' t cost too much and you have the benifit of being able to use factory or Ackley improved loads.