300 raptor or 300 rum

There is a custom rifle builder out of Montana who builds a long range rifle chambered in one of many of his wildcat rounds, the 300 Raptor. It fires a 200 grain pill at 3,565 Fps and 180 grains at 3650 Fps. Comes with a nightforce scope an all that. About a $5000 rifle. Or, should I stick to mainstream stuff and get a 300 rum, which with the right loads can get a 180 grain out at 3450 Fps

I have a 338 Lapua mag already but I want a 300 magnum cartridge. I have a 300 H&H but that is just a tad hotter than a 30-06. The 300 Raptor is a 338 Khan necked down to 300