It shouldn't matter whether or not the bullet would penetrate. Adamantium doesn't have magical properties that kill off people with healing factors. In the second X-men movie we see Wolverine get shot in the face by a cop with a normal lead and copper FMJ round when they were fleeing Bobby's (Iceman's) house. Granted the bullet should not have penetrated the Adamantium , but it did pierce his skull and it entered his brain, dropping him to the floor.
A few moments after we think he's dead, his healing factor pushes out the bullet and he returns to consciousness like nothing ever happened. An Adamantium bullet wouldn't do any different. And there is another factor that makes the Adamantium bullet impossible. The bullet would have to be able to conform to the grooves and lans in the barrel of a pistol or rifle.
A smooth bore shot gun would have worked for the Adamantium bullet concept, but not that revolver they had in the movie. Being Adamantium and being indestructible, the bullet would have gotten lodged in, and distended, the barrel and the gun would have blown up in Lauren's hand. Beyond that, the gun just happened to be in the appropriate caliber....not likely. The Adamantium bullet is a very weak point in an otherwise outstanding film.
- Normal FMJ pierced Wolverine's Adamantium skull in the second X-men film
- Wolverine fully recovered from the bullet to the head
- Neither the FMJ or the Adamantium bullet should be able to penetrate
- Even if the Adamantium bullet penetrated, wolverine, or at least X24, would have been able to heal through it
- Bullet would never have shot out of that revolver, both for reasons mentioned and not mentioned.