Well the envelope was completely collapsed. I was thinking a couple gun shots would only allow the gas to exit out those holes or tears making the decent much slower. Luke's kills went up in fire thanks to hydrogen. No worry here.
The Canadians tried to shoot down a weather balloon gone awry back in '98 and even after 1000 rounds of 20mm it didn't deflate, it then proceeded across the Atlantic before finally coming down in Finland. Talked to a contractor out in Iraq and he said the observation balloons there would regularly get shot up quite a bit and they rarely had deflation issues because of it.