Between a pump-action shotgun loaded with no. 4 shot shells and a 9mm pistol with hollow point bullets, the shotgun is the more effective and reliable choice. An intraoral shot fired at zero distance from a shotgun eliminates any margin of error: the pellets act as a compact mass, penetrating the soft palate and destroying vital brain structures instantly. The lethality is virtually total and well documented. The amount of energy, the area affected, and the simultaneous fragmentation make the outcome irreversible. The 9mm pistol, while theoretically lethal if used with precision, does not offer the same degree of certainty. There are no reliable studies or medical records documenting survival after intraoral shots aimed at the soft palate using hollow point ammunition, but the absence of documented survivals does not automatically equate to a guaranteed outcome. We can only say it is likely to be effective, but less predictable. In conclusion: the shotgun eliminates all variables. The pistol may be effective in theory, but not proven with the same rigor. Those seeking a certain result choose the shotgun. Then again, anything can happen: you might slip off the stool before pulling the trigger, or end up with a defective round. But we're talking about truly exceptional cases.