The point is you can take say 300 win mag add a grain or two and walla, you have ballistics equal to the RUM factory load at with 10 grains or moreLess powder. Most people don't handload and was making sure that someone doesn't get deer in the headlight look over ballistics thinking the RUM is the second coming.
I understand handloading and all that goes with it. Been there got the T shirt, Know about strecthed case , flatten primers etc etc. It's a fine hobby and one gets enjoyment out of loading one's own. I gave up reloading about 10 years ago when I discover some factory ammo was giving accuracy performance the couldn't be improved upon. I believe 1/8 -3/16 groups center to center would be hard to improve on out of a hunting rifle.I love how insults can fly. Fear I don't think go considering I owned 300 weatherby's over 30 years ago , along with a 338 in the past and presently have two 375 H & H 's hopefully to go to Africa in the near future.