I have been shooting one for about 8-9 years, I would have to look at my load data to be sure. I would have to agree with parts of the post above. Yes the brass soft,is a pain sometimes to make and does not last long. I use mine exclusivly for hunting so I don't fire a lot of shots a year. The brass is no harder to make than an Ackley round after you neck the case down. I shoot 180 Bal Tips at 3300 FPS and 165's at 3450 FPS. The 180 load is max in my rifle and near max in a few friends rifles. The 165 load is moderate. My rifle Rem 700 W/ Hart #5 at 25.5". I have 6 hunting buddies that now shoot the 300 Jarrett and we all swear by it. We have a fireforming barrel that we all have used including our gunsmith. The others are easier but I have yet to see 300 Weatherby shoot anywhere as accuratly. I have yet to try one of the RUM's.
Good Luck
Mark