I think I see the dent you are talking about. My first thought is that is most likely not the problem. I would first make sure the magazine spring is properly installed/oriented by taking the magazine apart. It has been seen where the mag spring was installed backwards. Plus I would even give the magazine a good cleaning inside while it's apart. Taurus has been known to use some pretty heavy packing grease. Don't oil the inside of the mag after cleaning.
Second thought would possibly be the extractor. Give it a real good look and make sure there are no tiny chips at the end and make sure it's clean under the edge where the case rim would sit.
Some smarter folks will be along to help out. Keep us posted.