The mag coil primary is in parallel with the breaker points, and one end is grounded.
Even with the points "OPEN" the primary coil winding provides a ground path.
In other words, with the points "OPEN" measuring from the common (insulated) junction of the coil primary, the points, and the condenser, you will get a low resistance reading, the next thing to a "short" to ground.
If your Ohmmeter is accurate at low resistance, the reading likely will be -n the range of .4 to .8 Ohms.
What are you "seeing" with yours?
Secondary resistance is likely in the 4000 to 6000 Ohm range.