Mike you got me thinking so I decided to measure my sights on my 450 3 1/4" BPE. The sight difference front to rear is .064" and they are 21" apart. Which means at 50 yds the barrels are pointing ~5.5" above the aim point.
When the weather breaks here and warms up I will go shoot it. However, for reference, my first loads will be 120 grains of black pushing a 270 gr hollow point copper tubed paper patch bullet.