Just something that I have gleaned from various sources in reading online sites from around the world,I cant put a finger exactly on one at all though.

Though a quick look just now came up with this quote

"The sixth edition of the Hornady Handbook shows that their potent 220 grain InterLock bullet can be driven at a MV of 2300 fps by 60.5 grains of RL-25 powder, and to a MV of 2800 fps by a maximum charge of 75.1 grains of RL-25. The latter is 100 fps faster than the top velocity attainable with this bullet in the .300 Rem SAUM, .300 WSM, or .300 Win. Magnum. These Hornady loads used Norma brass, WLRM primers, and were tested in a rifle with a 24" barrel.

The reloader will find that the .308 Norma will handle bullets heavier than 180 grains every bit as well as (or better than) the .300 Win. Magnum, and considerably better than the new short .300 WSM and .300 Rem. SAUM cartridges. Due to its combination of standard length, a longer neck than most of its competitors, and excellent Norma brass, the .308 Norma Magnum may be the all-around best .300 Magnum cartridge for the dedicated reloader."