Let's say I have a monster with DR 10/Adamantine.
Would it be correct to say that if a PC attacks that monster with a +3 non-Adamantine weapon, the monster's DR would not be overcome?
The general question here is whether magical weapons automatically overcome damage reduction. My read is that magical weapons can overcome DR, but it's not guaranteed. Is that correct?
Best Answer
Correct on both counts. See the PFSRD.
Thus, a +3 weapon over comes DR that is vulnerable to magic, cold iron, or silver, but not adamantine (unless it was actually made from adamantine). It would need +4 to overcome DR/adamantine without being adamantine.