Buddies .17Ackley Hornet in a thick side Martini, minimal taper case has no trouble running 3,940fps with 20gr., not a light load by any stroke, and cases kick completely out of the action upon extraction.

Another friend's .30/30AckImp also has no extraction problems from his Martini Cadet using loads that duplicate .300 Savage fctory ammo. It's the tapered cases that usually give grief in extraction, not the straight sided ones from what I've seen.

I've never had any extraction issues with straight-sided cases with heavy loads as there is little or very minimal bolt or block thrust, the barrel handling the pressure. The case then conracts roughly .001' away form the chamber walls and usually 'falls' from the chamber. Rough chambers don't work, anywhere.