I mentioned the engineering bulb specifically because a dedicated rush to that (avoid teching fishing to bulb that path) allows for 1000-500 BC type engineering timings. I think it was HR Oscar that won deity/normal/standard domination using that, around 1000 AD. By the time the AI got castles he had already killed/vassaled a few and had the production base to crank CR III treb + knights at which point nothing the AI gets pre-rifles stops you. Finishing outright by 1000 AD cuts most AI from getting to rifling even on deity and even if a few get it you're talking 3x anybody else's land by then. That's a niche strategy though, and nations that start with fishing (or need/want to use seafood early) can't use it. Draft rifles are by far the easiest to execute IMO, especially transitioning into rifle/cannon from there.