Not to debate on how to fix bulges, but rather what is going on with the metal. Bulges or dents or any other metal yielding cause plastic deformation. The initial deformation and the repair will both serve to strengthen the metal. If there is any thinning due to stretching or filing, this will have to be considered by measuring the final thickness. But let me say it again: this deformation will STRENGTHEN the metal. A barrle that has been cold worked by bulging/denting then cold worked again to remove it, that has say .030 wall in the end will be stronger than one that has not been cold worked of the same thickness. Whether or not you can work bulges out is a separable question.
The stuff being spread around these boards about being weaker is old wives tales.
