Experimental results on the propagation and transport efficiency of a 1 MV, 5 kA, 50 ns annular proton beam through a two‐stage linear induction accelerator are presented. The beam is generated in a magnetically insulated diode and propagates with high‐efficiency along a 0.6 T axial magnetic field to a second accelerating gap located 30 cm downstream. The second accelerating gap increases the beam energy to 1.3 MeV. A full‐cusp geometry provides the magnetic insulation in both the diode and the second gap. We report in this paper an 86% (±5%) transport efficiency and an increase of 1.6° in the beam divergence for propagation through the post acceleration gap.