Orcs are assumed to have been raised in a savage culture where combat and abuse are the norm. They thus have some amateur-class familiarity with various means of basic combat built into them at a very early age. They're still unlikely to become masters of it (they're still dumb as rocks, and improve slowly).

There were some older proposals about giving orcs an enhanced rate of learning weapons, but then it's much harder to explain why they're good at that but (e.g.) human warriors aren't. This seemed like a sensible way to give berserkers a small boost which made sense within the race.

valguarnera@carrionfields.com