Bret Devereaux

69% slaves with only a sword to enforce it doesn't seem feasible. Insurrection was a constant threat to slave-owners in the US at 50% slave and they had guns.

Ok, right but the problem here isn't if it 'seems feasible' - it happened. In any event, I think you over wildly overestimating the oppression capabilities of single-shot muskets with long reload times as compared to armored heavy infantry with spears.

well we think it happened is the point. Slaves could have been a lower %. Single shot guns were sufficiently superior that slave owners preferred them to spears. revealed preference is the key here.

They literally couldn't have been for the reasons I already mentioned: spartiates are legally barred from engaging in farming, but own most of the land, and require helots to farm that land in order to eat.

In any event, your assumption that a society couldn't push over 50% enslaved is just obviously, comically false. Haiti was 89% enslaved prior to its revolution and had been that was for decades before it produced the eventual successful revolt.

Right but in Haiti's case it needed guns and it failed. I'm not saying Sparta is impossible. More likely the healots weren't treated as badly and were more like a medieval peasant those ratios were enormous as well

Again, you are presuming the efficacy of guns in a firearms context is greater than the efficacy of contact weapons in a context without firearms and that just isn't correct. By way of example, finding themselves in a non-firearms environment dealing with being massively...

...outnumbered, Spanish conquistadors found their swords&pikes far more useful than their matchlock firearms & relied on contact weapons over missile weapons. On this point, see J.F. Guilmartin, "The Cutting Edge" in K.J. Andrien and R. Adorno, Transatlantic Encounters (1991).