I came across this beast in Ken Howell's book on custom cartridges. I'd never heard of it, and I'm curious what were the factory ballistics. It's a necked down .369 Purdey. Obviously it was meant to be competition to H&H's .30 Super Flanged Mag.

Bet not more than half a dozen rifles were ever made.

That's not a bet I'd care to take. Neither CH-4D nor HDS lists dies for the thing. Oddly, the CIP still lists a chamber pressure for the .369 itself, and I don't think it was exactly what one could call common. A google for the 369/30 turned up only two entries, but (amazingly) one was a listing at Sisk Rifles for a reamer. Are you here Charlie?

ASDF
Call Dave Kiff at Pacific Tool, 541-826-5808, he can make a reamer.
Charlie