  A high-precision half-life measurement for the superallowed Fermi $\beta^+$
emitter $^{22}$Mg was performed at the TRIUMF-ISAC facility using a 4$\pi$
proportional gas counter. The result of $T_{1/2} = 3.87400 \pm 0.00079$ s is a
factor of 3 more precise than the previously adopted world average and resolves
a discrepancy between the two previously published $^{22}$Mg half-life
measurements.
