Since then, though, PCs and monsters have been doing enough damage that breaking shields really should be a thing.
Here is how we'll try doing it:
Damage to Shields
A shield may take damage if deliberately targeted (GURPS Martial Arts, p. 112) or on any defense made by the shield user.
Shields . . .
- have HP per Basic Set Characters, p. 287, and DR
- take damage, minus DR on a successful block by the margin of the DB of the shield OR on a deliberate attack on a shield not Blocked or Dodged. Shields may take damage (or suffer other effects) on any Block from certain attack forms.
- are damaged as Homogenous.
- At 0 HP, the shield is damaged and possibly useless. Roll 1d. On a 1-3, your shield is broken off the handles and useless. On a 4-6, DB drops to 0 (light or small shield) or 1 (medium or large shield.) A DB 0 shield is hit on any Block roll made by a margin of 0.
Every hit after that point requires a HT roll (12, 14 for Fine shields); success means the shield continues to work as above; failure destroys the shield.
- Destroyed automatically at -1xHP.
This will make shields flimsier than Basic Set does (most will take 40-80 damage to break), but still fairly sturdy. Damage will be easy to deal with. And now there is an actual value to Shatterproofed shields and Orichalcum ones.
(Editing Later: However it will make shields sturdier than the rules in Low-Tech do. Another option is to just use those numbers, and let HP go down to -5xHP like anything else. More negative HP numbers, more variability in shield survival.)
We aren't using Overpenetration, (Basic Set Campaigns, p. 484) It's thematically inappropriate for DF.
What about Shieldslayer? It works as written; this does not change its effects at all. That's a special attack form. So are rust monster antennae, and some other special attacks.