Nzbiggunfan,
SO far testing the 338 Kahn I built for my 2000 yard rifle, the 300 gr Sierra is performing very well.
I will be getting a shipment of 300 gr ULD bullets from Wildcat bullets here pretty soon to test them as they have a B.C. substantially higher then the Sierra.
They also are working on a 350 gr ULD design for the 338" as well. Both of these bullets use a Rebated Boattail design which I have found to aid in throat life and accuracy.
For your needs though, the 338 Lapua has plenty of Horse power to muscle the 250 gr pills out to be completely effective at your 750 meter range.
In fact at top velocities, the 225 gr Nolser Accubond would probably shoot flatter then the 300 gr Sierra because of its velocity advantage. This would certainly not hold true at longer ranges but it would at shorter.
I would recommend the Sierra bullets but at $1 ea, thats pretty spendy.
Run the top lods over the ballistic calculator and I think the 225 gr and 250 gr BT's will suprise you at the ranges you wish to shoot at.
Good Shooting!!!
Kirby Allen(50)