I'm loading 130gr Speers and 150gr SST's and 150gr Hotcore with no problem from the 300 HAM'R using the mag length from the 300 blackout mags.
The gun is super accurate and fast for the case. My main hog hunting bullets I shoot a 110gr at 2780 FPS from a 16" barrel. I'm getting 2570 with 130 gainers.
I like to use the 110's for hogs because when we hunt the fields the key to getting more hogs is less recoil. I stopped using my 6.8 because it's much cheaper with the 300 HAM'R and performance meets our exceeds it.
The part that is appealing for the 300 HAM'R is its easy to convert a 5.56 because they use the same bolt. The brass is dirt cheap, less than half of 6.8 brass.
If you want to save money, especially if you handload, the 300 HAM'R is a great option. It's not there to replace any other cartridge, but to give an economical and very efficient option to many shooters.
If you want more recoil, higher costs, plenty of other cartridges out there to choose from.
And to shoot its effectiveness, friend using his 300 HAM'R with 130's to get rid of some hogs for one of the farmers.