The Stovebolt Site Forums The Shop Area Driveline Outer axle bearing removal.

Here's a snapshot from a 1929-46 Chevrolet Master Parts Book with the passenger and 1/2 ton truck rear axle exploded diagram. The red circled part (bearing retainer) is the thin metal ring you are catching inside the axle bearing and seal. According to a 1929-46 Chevrolet Truck Shop Manual, the original puller jaws need to be aligned vertically (to avoid catching welding flashing on the inner sides of the axle tube) to reach inside and grab the retainer ring, bearing and seal, then pull all at once.

I believe others have mentioned the inner bearing retainer often gets a little bent up during the extraction process, but can be easily flattened back out for reinstallation.