I admit to a soft spot for the RN in either bullet weight and caliber... I'm just too old school for my own good....
Actually credit for that load goes to an older Hornady Manual...
not "that Seafire" character...
Someone posted a pic of the two pages from that old Hornady manual on the favorite 7x57 loads thread. I copied it and filed it in my 7x57 notebook. I'm gonna give it a try, for sure. It's still surprising, though, after all these years that someone doesn't just include a "+P" section for the 7x57 in the manuals. If you compare the data in that old manual to the data in a new one, the new max loads are 5-6 grains less than shown in the old one. Two sections, one for old 93/95 Mausers and one for stronger rifles, would seem to be the ticket for beginning to wring top performance out of that old round.
By the way, if I understand correctly, the 154 gr RN Interlock has been discontinued. That's a shame.