I have been thinking of the same thing about the 7mag to a 25 caliber, does anyone have anymore insight on this ?

My reamer is set up exactly as tiggertate speaks. I sent a dummy round to the reamer manufacturer and as luck would have it, the throat is setup where the 140 Sierra`s jacket where the boattail begins is right on the neck/shoulder junction. When I put a 120 gr Nosler Ballistic Tip in the Stoney Point comparator, I was pleasantly suprised it is in the exact same place, the shorter boattail on the Nosler must be the reason. It is perfectly throated for my 2 favorite bullets!!