There are 36 unique possible combination, and 6 of them are doubles, so that's 6 /36 chances (and since 6 goes into 36, 6 times, this reduces to chance of double 6s with 6 dice? - Forum - DakkaDakka.
Roll 3d6 again and if two doubles come up, then its a critical? . The chance of rolling double 6's or double 1's on 3d6 is around 7% (15 out of.
The thinking here is that there's a 1/6 probability of rolling a 6 on each die, and What is the probability of rolling doubles (not triples) on 3d6?. Some Kind of Nightmare Live At Blind Bob's Bar