I'm amazed people would even consider reusing a bulged case in these high pressure calibers. Over the years mfg's have strengthened the web area of the 9mm & 40s&w cases for a reason. Any time your moving that much brass back into place it will weaken that area. I've showed this photo before, these were fired from a s&w shield. I sized them just to see how bad the ring looked that gets left on the brass after "swaging" them back into shape. When you move that much material you're actually swaging/reforming not sizing. I did this to keep myself fresh on what to look for when inspecting range brass that I plan on using. Myself I toss anything with a bulge, too scratched up, has a wear ring (see picture below) at the case wall/web junction point on the sidewall of the case.
If you've ever had it happen or witnessed when 1 of these cases gives up the ghost when in the chambered/fired You wouldn't think about reusing a bulged case ever again. I've seen it happen 3 times over the decades, 2 of them were 9mm's & 1 was an overcharged 45acp. All 3 were with all metal/metal framed firearms. 2 of them were 1911's and a star 9mm, all with fully supported chambers.
The 1st thing that happens is you drop the pistol. The mag blows out the bottom and is typically destroyed. Sometimes the mag release survives but more often then not it will need replaced. Or if your lucky re-tuned/adjusted. You dropped the pistol because the grips blow off under your fingers. Wood grips don't survive, most rubber grips don't make it either or need washers under the hold down screws to stay in place. Bolt faces & extractors get beat up and it's common to replace the extractor and tune the new one.
The real concern is your hand/hands that were lucky enough to be holds that pistol that just grenade'd over a $.05 piece of brass. You'll get that warm fuzzy feeling when a firecracker goes off in your hand at the very least. From there it could be more like a M-80, pieces of the grip sticking in your hand, metal from the mag, jagged metal in your hands/arms/body/face from the exploded case. Nor can you rule out pieces of metal off the firearm.
I'm not trying to start anything or promote doom & gloom. I've seen 1st hand what happens when cases explode in the web area in pistols when fired. It never ended well for the shooter.
I'm sure others will chime in say they've been using bulged brass for years. I wish them the best & hope nothing happens to them.
Myself, it isn't worth the cost of the brass to me, stay safe.
