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I don't have any pics, however it would look the same as any other KB from a bore obstruction.

Many full metal jacket bullets are not actually "full" metal jackets. The base of the bullet is not covered by copper. Since it isn't covered the jacket can easily separate since most of the gas pressure is pressing on the lead core of the bullet. This is due to the manufacturing process of the bullets. Copper jackets are formed with the base open to allow a lead core to be pressed in place, then the core is crimped into place by rolling the base of the copper jacket back onto the core.

You can clearly see how the base of a FMJ is constructed in the following picture. Although the bullets depicted are rifle bullets, pistol bullets are constructed the same.

Gyrogearhead wrote:

...if you apply a crimp and press the cartridge mouth into the bullet the cartridge won't headspace properly.

When you said "crimp" I believe you intended to say "roll crimp". Roll crimp is definately something you don't want on a 45ACP or 9mm cartridge.

I did not intend to say "roll crimp." It is possible to press a case into the bullet with some "taper crimp" dies. On cases that headspace on the cartridge mouth this is a problem, just as not removing the bell is a problem.

I feel I should add that the term "taper crimp" is a bit of a misnomer. You aren't actually crimping anything, you are removing the bell that you added to help seat the bullet. On straight walled cartridges (45 Automatic) and tapered cartridges (9mm Luger) the cartridge headspaces on the case mouth; if you apply a crimp and press the cartridge mouth into the bullet the cartridge won't headspace properly. Another danger with jacketed bullets is the possibility of piercing the jacket and causing it to separate from the core in the barrel. A subsequent shot will hit the separated jacket and could cause a ka-boom in the same manner a squib will.