Alright GRAAHH, I added the blast shield. For this save I assume that the window is ~2.5m tall.
I mean, if you use a radiation proof blast shield then you wouldn't need to be that far away. You could easily plant it, get behind the shield, set it off, wait a second, and then move in.
this isn't a breaching charge, it's basically a nuclear weapon (still great for breaching though, if you want to breach the bedrock layer of the surrounding area).
Update: Improved backblast suppression capability, made target armor plate thicker, and added BMTL targets.
The only breaching charge capable of causing an international incident from withing your own borders.