The extractor in your Mausingfield action should be able to snap over the rim of the cartridge. If it doesn't we can easily fix that for you if you send your action to us.
As for the case jumping forward and away from the bolt face upon release from the magazine, that's solely a function of the shape of the case and the length of the magazine feed lips. There's nothing magic about this stuff. The bolt does not attract the case to ensure that the case rim comes up the bolt face and underneath the extractor claw. What's causing the case to jump forward on its way of of the magazine is contact with the shoulder of the case below it. The Mausingfield and other CRF actions will generally function better if the case is released earlier, before the angled shoulder of the case below can engage the head of the case being fed. I like the AICS mags, they are well made, but I have never hesitated to shorten their feed lips to improve the cooperation between mag and action. ARC mags have shorter feed lips than AI mags and copies, such as the Accurate mags. AI actions are not controlled round feed (CRF), they're push feeds, and releasing the cartridge a bit later is a good thing for most push-feed actions.
Controlled-round-feed is a bit of a misnomer. The bolt can only take control of the cartridge if presented (released) correctly. The faster you run the bolt, the less of an issue this becomes so I'm surprised by your claim of experiencing the issue at high bolt speeds. Are you running a 223?
Remember, when Mauser first figured this stuff out in the 1890's, he shaped the actions mag well surfaces to release the cartridges at the right time. Maybe early cartridge engagement (ECE) would be a more accurate name for CRF actions. Let's see if that sticks.
Ted
