ORIGINAL: cayugad
I think he went with the Lyman 57SMT since it attaches to the side of the Ultra Mag with no drilling. Its already tapped for the peep sight. Some of them were getting marble front sights and Redclub shoots the same set up. He was shooting groups at 200 yards with the open peep sight using his elk load. It was pretty impressive...
Well, I'm finally catching up on this topic, been out of the loop for awhile. Just talked to Sabotloader on the phone.
Yes, I have put the Lyman 57SMT on 3 U-Ms. My brother also put one on his. You will need to change out the front sight also. I can dig out that info if you need it.
I have a White Lightning also and I mounted a scope on it, but I also bought a Williams peepsite for it. The Lyman won't work with the Lightning. I am pretty sure the Williams will also work on the U-M. Not sure which one I like better, they both seem to have their advantages/disadvantages. Maybe get away without changing the front sight if you get the Williams.
Regarding the Bullshops. I think the .5045's will be perfect for you. All 4 U-M's in my family like the .5045's. They don't shoot any better than the .504's, but will definitely give you a better feeling that they will not slide off the load. Let me know if you have any other questions.