Explosives Options

[p00ya]

It's kinda hard to see how explosive damage against barriers works in SR4a.

An explosive's Damage Value is calculated as (modified) rating x the square root of the kilograms used.

Instead of planting a 5kg charge, with rating * 2.2 DV, why not plant 5 1kg charges? Then there are 5 attacks of DV = rating * 1, the only downsides are that it takes longer to plant and the separation of attacks means you can't just edge once.

The second question applies to planting explosives on large barriers. The rules imply you keep a damage counter for each 1sqm area of the barrier.

The Structure rating is the number of "damage boxes" required to destroy a section 1 meter square and about 10 cm thick)

If you detonate one explosive charge on a barrier, but the damage is insufficient to "make a hole", you then track the blast effect out until the damage diminishes to 0. You can then apply charges anywhere on the weakened areas to finish them off. Damage in excess of the "structure rating" remaining spills over to adjacent squares. Does this interpretation look right?

[Saint Sithney]

Your character has a demolitions skill. That is what is used to determine any increase in damage/efficiency for a specifically tasked explosive charge. Any actual knowledge you bring into the equation is just meta-gaming. Also, if a charge isn't sufficient to breach, it isn't considered sufficient to cause any damage to that material.

As to why you would want to use one 4kg charge to double your force rather than using four 1kg charges and attempting to create sympathetic blast waves to break through a well-reinforced door, well, let's just say the demo rules aren't all that complex. Besides, setting up an explosion so that the blastwaves are perfectly engineered to crack a blast door, is basically untenable in most of the run and gun scenarios where satchel charges see play. Finally, explosives can already have their force doubled or tripled using good tamping techniques as laid out in arsenal.