40 2 1/2 bullet diameter

[Don McDowell]

1 grain of 1 1/2 probably won't gain you much over 5 fps. But the important thing is whether or not the rifle likes that extra grain/grains of powder or not

[SchuetzenDave]

Caliber 0.408 Inches
Bullet Weight 410 Grains
Bullet Length 1.321 Inches
Barrel Twist 16 Inches/turn
muzzle velocity 1323 fps
Temperature 50 degrees Fahrenheit (59 is standard)
Pressure 29.92 inches of mercury (29.92 is standard)

Sg = 2.42

Drop in velocity did not change the Sg much.