Seems to me a great application for the 300BLK would be the younger shooter, some female shooters, and the slight of build shooters. This,for deer,hogs,and even for coyotes where you were not selling primed pelts.
With some bullets you can get out there to 250 yards with adequate killing power for deer and hogs. For coyotes it would be good for 400 yards if you have the scope to help.
For this,handloading will help greatly,as will a non-gas gun. There are more than just a few bullets <126grs that work well. Another help to the long(er) range shooter will be the scope with target turrets or a system like Nikon has with a BDC reticle supported by the manufacturers ballistic program.
More fathers should be teaching shot placement vs a higher power chambering such as 243 or 7-08. Shot placement is the key not a higher power round. If you get this wrong,the child will have to suffer through unneeded recoil and blast overpressures.
The 300BLK chambering will not do it all. But it will deliver more energy at longer ranges than needed by a big percentage of hunters.
We have made countless one shot kills on some of the biggest hogs in our area. Not just CNS hits either. A double lung shot on a 200lb+,thick plated boar hog,will put him on the ground in less than 30yds. Some much less.
Pick your bullet,pick your action,pick your distance,put the shot where it is supposed to be,the 300BLK is a good killer if you do your part. --- SAWMAN