A good, stout door will protect people from a lot of dangers. It will not, however, save enemies of the U.S. from America's armed forces. While troops can usually open a door with a swift donkey kick or a battering ram, they also have more violent ways of making an entrance.
1. Rifle-fired grenades
The Simon grenade rifle entry munition, or GREM, is mounted on the end of a M-16 rifle or M-4 carbine. The weapon's standard 5.56mm round is fired, striking the grenade and sending it 15-30 meters to the target door. Once the grenade's standoff rod strikes the target, the grenade detonates and opens the door — violently.
2. Standard breaching charges
When firing a grenade isn't an option, troops can just plant an explosive on the door.
3. Water charge
A modification of the standard explosive charge, water charges reduce the risk of injury to the breachers or the people on the other side of the door. Standard explosives sandwiched between containers of water are placed on the door and detonated. Water bottles are commonly used, but this video was filmed using IV bags.
Of course, service members who are already carrying a shotgun would probably prefer to just use it. Troops press the barrel against the frame, aiming for hinge points or where bolts pass through the frame. Once the round rips through the wood, the door can be quickly kicked or pushed open.
5. Blowing out an entire wall
Sometimes it's not a good idea to go through the door at all. In that case, there are a few ways to rig explosives to make a new opening in a wall. In this video, det cord was placed on a marksmanship target to create a large, oval-shaped explosive and the whole thing was stuck to the wall. When detonated, it makes a hole big enough to run through. To go straight to the explosion in the video, skip to 2:20.
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