A friend of mine bought the Lyman Peep and tried it on his Lyman trade rifle. It worked good but he didn't like it or need it as he has young strong eyes.
I talked him out of it and installed it on my cabela's Hawken. I drilled out the peep hole to 1/8" and it made a world of difference for my old eyes. I could not see the open sights very well but with the peep, I can keep all my shots wher they need to be on deer out to about 80 yards. Much better than what I was able to see before.
I was going to try one of those tang mounted T/C sights but since this one was available, I went with it.