From the governing equation $$-(3+1)$$ - ( 3 + 1 ) -dimensional nonlinear Schrödinger equation with cubic-quintic-septimal nonlinearities, different diffractions and $${\mathcal {PT}}$$ PT -symmetric potentials, we obtain two kinds of analytical Gaussian-type light bullet solutions. The septimal nonlinear term has a strong impact on the formation of light bullets. The eigenvalue method and direct numerical simulation to analytical solutions imply that stable and unstable evolution of light bullets against white noise attributes to the coaction of cubic-quintic-septimal nonlinearities, dispersion, different diffractions and $${\mathcal {PT}}$$ PT -symmetric potential.