m1a and calibrated scope question?

[nova512]

i have a springfield m1a and a springfield scope that is calibrated to 168 grn graduated out to 700 yards by the hundred.how much of a difference say out to 400 would it be with 147 grn?im gonna be reloading for it but i have some battle packs with that grain tring to get an idea of how it will do.​

 

[red_zr24x4]

Your best bet is to go shoot them from a rest where you know the gun is set solid.
That will give you the actual difference. Shoot both weight bullets at different targets so you can tell them apart.

 

[Yeah]

147 grain WWB versus FGMM at 400? -30.7/14.4 and -33.9/13.8 respectively, with a 10MPH full value wind using published velocity.

Change is the bane of BDC turrets.