Not sure of the age of this one, I have had it for at least 20 years. When I had a TC Contender barrel, I used this on stray varmints and once in a while a rabbit or squirrel.
I have the same in a 2 cavity Lyman block. I have been shooting a few of those in the AR, not sure that I like it yet. We have been so cold and wet this winter, I have not gotten to put any on paper, only a few over the chronograph so far.