"So, Ulthar," you begin. "What's this about a siege weapon in the armoury?"
He winces. "That's-" he begins, then considers. "The amount you've already done, I'll not shut you out. Don't go repeating this to your manling friends, mind."
"I swear," you say instantly. And truthfully, too. You might report whatever he says to your superiors in the Grey College, but they're not exactly your friends, are they?
"Well, before the Time of Woes was the War of Vengeance, and before the War of Vengeance we actually somehow got along with the pointy-eared buggers. If you believe the stories - and maybe you shouldn't, because there's many a Longbeard that considers history to be the ore one smelts and shapes - we were stupid enough to teach the bastards the secrets of torsion and tension so their sailors could defend their trade ships. What Kragg found in that armoury, and somehow prevented himself from smashing to pieces, appears to be a proof of concept. A bolt thrower that fires six lesser bolts between reloads." He shrugs, and drinks. "O'course, that could all be krut. Maybe some cheeky Engineer decided to tweak some noses by proving whatever Elgi could do, Dawi could do better. Maybe the stupid thing doesn't even work, which is why it was sealed up in the Armoury instead of fighting and dying with the rest of the Hold. Whatever it is, it's Durin's problem now."