Only the OP can answer his question based on his intended use.
He didn’t mention if he reloaded, that certainly changes the options.
I’d imagine the 6.5prc would cover most hunting scenarios. Unfortunately its maxed out with ~150gn bullets. Either way its plenty for medium sized game, probably lacking in lead for very large animals.
The 300prc certainly doesn’t do the same thing as a 6.5prc. The 300 is a boomer of a cartridge built to fire the largest of the 300gn projectiles.
The 7prc looks like its also a boomer. I figured the 7prc would have been a 7mm version of the 6.5 prc but instead Hornady went with a much larger case. It’ll certainly have the capability for long range and any North American game. Question is how long you want to wait for components.
Who is shooting 300 grain bullets in the 300 PRC? For.hunting most are using 180-200 grain bullets. I have shot moose and large bears, goats and elk with a 6.5 Rem Mag using 140 grain pills and I doubt you could tell the difference from a .30 cal Mag with 180 or 200, and the end result was pretty much the same. If you add a 100 grains to the bullets and 0.07+ to the bore you start seeing a significant difference in effect... which is what I would do in setting up a pair of rifles for hunting. JMO.