Small Concealed Shaped Explosives, Spy Gear Booby Traps Options

[Jizmack]

I am trying to build small concealed shaped explosives, using Shadowrun equipment and skills, for the purpose of assassinating a target; analogous to poisoning someone.

I have one example: Explosive Beer Bottle

The explosive is designed to detonate only when the bottle is opened and the fluid (beer) comes in contact with a conductive electrical ground (saline inside the mouth). This triggers a small electric discharge in the detonator, which in turn triggers the explosive charge. The intention is to have the bottle explode directly in front of the target’s face.

However, by using the general rules I came up with the following:
Explosive Type: Explosive Foam (Rating 13).
Explosive Placement: Inside dark glass bottle.
Explosive Amount = 25 grams = 0.025 kilograms (it cannot be much more than this if you want to prevent detection).
Explosive Damage Value = [13] x [0.025^0.5] = 2 DV.

Realistically, 25 grams of high explosives should be enough to blow someone’s face off and cush their frontal skull. In order to increase the DV to a reasonable level, I looked at the following rules:

Directional Explosion Blast: in the core rules this improves the blast strength loss from –2 DV per meter to –1 DV per meter. How would this improve the DV at point blank range? Maybe increase it by 1.5X (2DV becomes 3DV)?

Called Shot: In normal combat, targeting the head/face increases the DV by +4. Can this be applied in this case?

Surprise: The target would obviously not know what hit him, so no Dodge or defending in any way.

If all rules apply, then the DV would become 7, and assuming there is no armor on the face, it would be a strait Body test to resist the Damage. This means that it is still basically impossible to kill someone in this manner. The guy would have a very bad day, but alive.

Any ideas from the group to make this more realistic?
Much appreciated (IMG:style_emoticons/default/smile.gif)