Velocity Flat Spot
Also: Flat Spot
A charge-weight range where measured muzzle velocity barely changes, which some handloaders read as a stable accuracy node.
A velocity flat spot is a span of charge weights over which a chronograph shows little or no rise in muzzle velocity, even as you add powder. Handloaders who see this on a load ladder often interpret the plateau as a sign that the load is insensitive to small charge variations, and they center the final charge inside it. The reasoning is that a charge tolerant of tenths of a grain should also tolerate the normal scatter of load development.
Whether flat spots are real and repeatable is genuinely contested. Critics point out that with only a few shots per charge, the apparent plateau can be an artifact of normal velocity scatter rather than a true node, and that larger sample sizes often make it vanish. The neutral position is to treat a flat spot as a candidate worth confirming with more rounds, not as proof on its own.