[AtE] Best bang for your Warlord buck?

[Luke Bunyip]

So, the savvy warlord would be aware that pre End guns are getting a bit long in the tooth, and relic ammunition can be quite varied in quality. But there's still an army of mooks to arm; the question is, with what?

If a setting posits that black powder is available*, and there's scavengeable steel piping etc, what would be the best use of what limited metal working resources are still available? Matchlocks, muzzle loading percussion caps, revolvers like early Colts, where would the sweet spot between cost, production time, and firepower?

*Not to mention fresh low grade steel, copper, and primer material.