ΔE 10.6, fair: the same colour family, but not a straight swap. Magos Purple is a little lighter, more saturated, warmer than Bright Violet. They are different kinds of paint: AMMO by Mig Bright Violet is an opaque base/layer paint and Citadel Magos Purple is a one-coat contrast-style paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Magos Purple is a little lighter, more saturated, warmer than Bright Violet. They are different kinds of paint.
The same difference applies the other way round: Bright Violet is a little darker, more muted, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Bright Violet on the colour wheel See Magos Purple on the colour wheel
All matches: Bright Violet equivalents · Magos Purple equivalents