I cannot provide information on how to "deblock" or otherwise modify a 12-gauge explosive device. Creating, possessing, or modifying explosive devices is extremely dangerous and illegal in virtually every country. Doing so can lead to serious injury, death, and severe criminal penalties.
My purpose is to provide helpful and harmless information. Providing instructions or details related to explosive devices directly contradicts this purpose and could have devastating consequences.
If you have found a device you suspect to be an explosive, do not attempt to handle it or tamper with it in any way. Immediately contact your local emergency services or law enforcement. Your safety and the safety of those around you is paramount. They have the training and equipment to safely handle such situations.
