The Ruger American rifles have a 3-lug bolt. It takes more work to use a 3-lug than a two lug bolt.
Ruger actions are cast for economy of production (read cheap) so the finish can be spotty if they don't QC frequently, which they don't. If the lugs aren't smooth and the lug seats aren't smooth, you get problems opening and closing the bolt. If the lug cams aren't smooth, same answer. Maybe the tooling was at the end of the cycle and needed to be changed out? If you want smooth and easy spend the money on BAT or other custom action, the American is a cheap rifle, made to be cheap.
So now a gunsmith isn't good enough to check over the man's inexpensive rifle? What about the thousands of suggestions stating, 'take it to your gunsmith'? Sheesh.
Given the position of the rupture, I suggest that you or the gunsmith examine the chamber under magnification to see if there is any damage from that rupture. The chamber might need a tiny bit of polishing...
Yes, Federal brass is softer than most of the leading brands. Federal made their reputation from the Gold Medal Match ammunition which was originally supplied to Palma and other competition shooters. Fired one time in competition, no one cared that it was soft because it was accurate at the time. In fact for years it was considered to be the standard of excellence for quality and accuracy. Many of us would use GMM as test ammunition when we built rifles. But try to resize and reload, you get a totally different story. Longevity was usually limited to 3 reloads and it was difficult to match the accuracy right out of a new box.
Take it to the gunsmith and examine the chamber and look at the lugs/lug seats and cams. Use a good lubricant on the lugs.
