Ok, it seems like several people are reporting the same sort of problem. I'm wondering if this a qc or technique problem? The savage mag should be inserted back to front. I push the rear of the mag in as far as it will go, the squeeze / slight pivot towards front until the catch clicks into place. I have never had a problem with misfeeds or breakage doing this.

If you try to push the mag straight up into the magwell, it will produce the failure you describe.