Can Anyone Name this Cartridge?

[Bob Wright]

Here are some interesting primer designs.
If the base is attracted to a magnet it may be the first picture.
The second picture describes a cup place over the cartridge and roll crimped. Yours appears to have a crimp around the cartridge near the base.

 

[jraulsten]

I think it is an "inside-primer" type cartridge......

 

[Croomrider]

That 50-70 Government fits the dimensions very well. I think that is a good possibility.

 

[Croomrider]

Then again, it seems to be the wrong primer type, but the size is close!