Any programs out there for designing cartridges?

[BlueFlyer]

regardless of whether it is belted, shoulder, mouth or other supposed method, it is actually the extractor that controls head space.

When I chamber a barrel, I remove the extractor and control the bolt face to headspace feature (shoulder, belt, rim) to get the headspace correct.
The extractor should have clearance to the rim to allow the rim to slide under the claw freely.
I am sure there are some exceptions out there.