I've been thinking about this a bit - what advantage would there be in a rifle-type weapon, when magic can do so much more? Well, if it's an alchemy-based weapon, it solves the issue - it can be a weapon that projects fire BUT DOESN'T REQUIRE ONE TO BE A MAGIC USER TO USE. Especially in "oh-gosh-it'smagic-it-must-be-evil!" Skyrim. If your local healer can whip up a powder/paste/potion that powers the weapon, it would be far more acceptable to the locals. Plus, push it as "fight fire with fire" anti-mage protection. Manufacture? I seem to remember a term from somewhere - dwemer tubes. With all the ruins everywhere, scavenging parts wouldn't be too hard. Shoot, any redneck worth his salt can make a potato gun with enough duct tape. I think there could believeably be a skilled craftsman (in Markarth or Windhelm, say) who might be working with Calcemo to restore Dwemer artifacts (for the museum), and as a side project, develop this. Think of it - a non-mage peasant could take a healer's potion and put it into one end of a metal and wood stick and make fire come out the other end. No spells. The only thing you gotta learn is where to point. It would be impractical, and nobody could manufacture them. If the Dwemer couldn't make anything like this at their height (which they didn't), neither could any contemporary. You effectively need the beginnings of Industry and an industrial revolution. Neither of which are present in Skyrim. Now a rudimentary hand cannon, or an actual ship gun (cannon), or Mortar is a lot easier to make. You don't need micro casting and smelting techniques. And they would still be crude, inaccurate, dangerous to operate weapons anyway. Not really no, guns were invented in medieval China and used in Medieval Europe, before mass produced steel or even the ability tosingle forge a single piece canon together existed. You know why they call it the barrel of a gun, because before they could make a solid bore canon, they had to make them in staves with loops, like a barrel.