EGW Practical Ballester Molina Extractor
The steel available today is of much higher quality than what was available when the original extractors were produced for this gun. Improvements to the entire manufacturing process include better alloys, more controlled furnaces, vacuum heat treat, better tooling, and finite element analysis-all of which EGW uses in production.
They found that the extractor rides up the relief groove on the ammunition casing with each round fired: this dulls the hook from constantly banging the case, over time tension is lost, leading to a jammed case which adversely affects accuracy. If you experience a loss of tension or must continually retension your extractor, it is time to replace it.
They fixed all 3 of these problems by reducing the distance from the bolt face to the extractor hook.
They found that most hook designs are cut straight at a right angle. They machined theirs at an acute angle so that there is more surface area for the hook to bite into the case. Right angles are a weak point on other extractors so they put radii on both sides of theirs to increase strength. The hook is machined with a special cutter that leaves a nice clean radius in the inside corner where most extractors fail.
Lastly their extractor is vacuum heat treated yielding great spring properties and the capability to maintain tension for 70,000+ rounds.