I am shooting a 300 SAUM and really like it. I call it my 308 Fatso. Think of it along the lines of a souped up 308 instead of a scaled down 300 RUM and you are in the right frame of mind for what you can do with this cartridge.
I don't know why everyone immediately compares it to the 300 WSM
. There is plenty of room for short 30 cal guns. If we all had to standardize we would all be shooting a 30-06.
No reaming to be done. At about 2.85" magazine length I could not even put an empty RUM case in it.