Well, I think I got the problem solved. Turns out that the trigger spring was loose. I started to notice a "hitch" in the trigger pull, and all of a sudden the trigger just went limp. I took off the grips and the spring was just sitting there. I put a fresh spring on and took it to the range. Put about 40 rounds down range - Magtech, Hornaday Defense and American Eagle Target & Range ammo all shot flawlessly. Remington UMC put down ten rounds, with one stovepipe (but no problem with the rounds seating into the barrel.) Considering that those ammos are not necessarily the ones always recommended, and that they shot fine save for the Remington, I'm thinking I'm in good shape. I did have a tough time getting the loop of the new trigger spring on but finally got it to fit. (If anyone has advice on making that an easier process, I'd be grateful for the information.) Also, when I went to remove the grips I noticed those were loose. Don't know what that was and I'm not sure but I'm thinking that perhaps that could have led to some of my problems - I don't know if the grip is meant to hold the trigger spring in place. Anyway, many thanks to all that commented, and good shooting!