Primary extraction

The case is not chemically sticking as it still rotates with the bolt, gripped by the extractor claw on the rim.

The mechanical sticking effect is a result from the case having expanded due to the high pressures during firing, and the extra initial force required can, depending on firearm design, make the extraction difficult for the user.

The camming action seen in many bolt-action rifles is an example of mechanical advantage being used for chambering and extraction.

[citation needed] The Blaser R8 straight-pull rifle design has been reported to have no issues with primary extraction.

The Heym SR 30 is another successful straight-pull design which features a bolt with ball bearings as locking elements.

Bolt-action rifles utilize a rotating camming action as a mechanical advantage to aid primary extraction, followed by a linear motion in the secondary extraction.
Disassembled bolt of the Heym SR 30.