Well, ok, it is interesting seeing the range or reactions to this question. As far as being overreactive to "something I read on the Internet," I am not usually. However, I regard the consequences of having a bad experience with high-pressure rounds serious enough to err on the side of caution.
I sould add that about eight years ago I won the double-charged subsonic Winchester .22 lottery one afternoon in my backyard. The result of getting one of the very few boxes of this defective ammunition blew up my Ruger 77-22 magazine into very small pieces at my feet and the extractor vanished to parts unknown. Instead of being nice and quiet, it sounded like a shotgun going off and it was only dumb luck that my arm wasn't under the magazine when it went up.
So, with the memory of this in mind, today I bagged up the .223 and took it to the dump with the rest of the trash, and chunked it in. End of story, not a huge loss, and I feel better. Again, thanks for the reactions and well-meaning advice.