Door Breacher Charges don't have a fixed spawn, so checking the same building on every deployment won't guarantee you'll find one. There are two practical routes: check the Vendor FOB Station when its daily stock changes, or find the recipe while looting Hajin and craft the charge at a 3D Printer. Buying one skips the recipe hunt, but availability can change before your next run. If you're planning a focused session, MW4 Bot Lobbies (https://www.u4gm.com/cod-mw4/bot-lobbies) may fit into your broader setup; the charge itself still comes down to a lucky purchase or recipe find. Treat it as a bonus, not the centre of your plan.
Check the Door Before Spending a Charge
Before carrying one, know which doors are worth using it on. The charge works on locked doors, including rooms that would normally call for a hard-to-find key, but it's consumed after one use. It won't open Gun Lockers or the Supreme Leader's Bunker, and it can't get past a keycard requirement. Lockers are off limits, too. A trip to the Air Base is a poor bet if the charge is your only reason for going. Check what you're facing, then save the item for a room you can actually enter.
Recipe and Crafting Materials
Have the recipe before heading to the printer. You'll need one unit of Experimental Compounds, obtained by defeating Commanders; five Stock Rods, found at the Imjin Farmland rice mill, the Hajin City construction zone, or Namjjog Station; and three Volatile Explosives. Look for those explosives in the NuriGO Mall DRC lab, the chemical buildings in the Citadel Prison Yard, or the storage tents at Imjin Farmland. Since the components come from several areas, check what you still need before choosing where to search.
How to Use It
At a qualifying locked door, interact as though you have the matching key. When the game asks for it, keep holding the interact button to use the Door Breacher Charge instead. The door opens without the key, but the charge is spent in the process. If you're moving quickly, it's easy to tap the button and miss the prompt, so hold it until the action completes. Once inside, stay alert and make sure your squad is ready to move.
Save It for a Useful Entry
Weigh the room against the cost of losing your only charge. A high-tier locked room with a clear exit may be worth opening; a locker, keycard door, or restricted bunker isn't. Keep track of the item if you find one, since another player may take it if you fall before extraction. For players arranging their next run, MW4 Boosting for sale (https://www.u4gm.com/cod-mw4/boosting) can sit alongside other preparation options, but it won't change which doors this tool can open. Use the charge deliberately, and leave with the loot only when the route back looks clear.