School me on ejector ramps

[Slash2]

More precisely, the interaction between the ramp and the ejector, why it pushes the ejector up and little bit away from fulling engaging the case rim when the bolt closes and not just allowing the extractor to grab as much as it can.
I ask because I have a lever gun that doesn't always extract the spend case, it is fairly new gun with a new extractor and a replacement extractor.
The case is not stuck, it can be removed with a little finger nail, it just seems that the ramp is pushing the extractor too far from the rim and sometimes it doesn't catch.
Before I start filing, honing and reshaping I would like to know what dynamics are at play in the interaction of these two parts.

[ar15barrels]

You have to balance this carefully.
You want as little ramp in the barrel as possible because that ramp weakens the chamber support.
There should be just enough ramp to make clearance for the extractor to nestle in behind the case's rim.
You want as much extractor engagement as possible though so you can't shorten the extractor too much either.

Sometimes, the angle of the extractor does not match up with the barrel's cut and simple matching up those angles by re-cutting the extractor's clearance angle will allow for more rim engagement without sacrificing chamber strength or extractor hook face length.

Dykem or sharpie the extractor and see where it's rubbing.

[Slash2]

You have to balance this carefully.
You want as little ramp in the barrel as possible because that ramp weakens the chamber support.
There should be just enough ramp to make clearance for the extractor to nestle in behind the case's rim.
You want as much extractor engagement as possible though so you can't shorten the extractor too much either.

Sometimes, the angle of the extractor does not match up with the barrel's cut and simple matching up those angles by re-cutting the extractor will allow for more rim engagement without sacrificing chamber strength or extractor hook face length.

Is it necessary for the extractor to contact the ramp at all? Say if one could stone down the front of the extractor enough that it is no longer pushed outward by the ramp, without reducing the hook face, would that be okay? Theoretically speaking of course.

[ar15barrels]

Is it necessary for the extractor to contact the ramp at all? Say if one could stone down the front of the extractor enough that it is no longer pushed outward by the ramp, without reducing the hook face, would that be okay? Theoretically speaking of course.

It does not need to contact the ramp if the ammo fits the chamber well.
The ramp is just a relief to make space for it.
However, if the chamber is sloppy, it's probably better for the cartridge NOT to be pushed to one side of the chamber.

If you could stone the front to increase engagement without reducing the hook face, you are doing exactly what I said above about matching the angles better.

[Slash2]

It does not need to contact the ramp if the ammo fits the chamber well.
The ramp is just a relief to make space for it.
However, if the chamber is sloppy, it's probably better for the cartridge NOT to be pushed to one side of the chamber.

If you could stone the front to increase engagement without reducing the hook face, you are doing exactly what I said above about matching the angles better.

Thanks Randall, that's what I figured, I just didn't want to assume that it was okay to hog away and then find out there was some mysterious subtle interaction between the two that effects case expansion or the time space continuum or something. Better to ask before cutting than ask about fixing.