I never said the extractor was weak - just inefficient, almost no primary extraction and lots to go wrong with a bit of crud. Just take a look at the patent link I posted. It certainly is much less efficient than the martini extractor. here some pics of my Swinburne:

It works with a V-spring poweringa massive internal hammer, apparently the firing pin was a bit delicate (the other rifle has a replaced firing pin). The extractor is lever-actuated, through a sliding extension on the bottom of the trigger guard, which pushes against the extractor proper - maybe not an issue with modern drawn brass, but with a sticky case, you need a rod to get the case out... Lots of lost power in the power transfer from lever to extractor.

This one is original finish, with all the bells and whistles - checkering, barrel ribs, wiping stick, engraving, rear express sights, windage adjustable front, patchbox... Even the trigger and lever are checkered, and it has a trigger stop.