Nonstationary self-consistent kinetic models of Xe-Sr laser on 6s2S → 5p2P3/2 (λ = 430.5 nm) transition in strontium ion and of Xe-Sr lamp pumped with a hard ionizer have been developed. Optimum conditions of lasing providing the laser efficiency relative to the pump of up to 3% have been realized. The efficiency of a source of spontaneous line radiation in the range 400-500 nm was shown to reach 30%.