I can not speak to the Mountaineer. But I can tell you that the LRH is one fine rifle. I have shot mine very accurately to 200 yards. I personally like a little heavier rifle to hunt with. I just ordered the conversion on the recommendation of a few guys here that will allow me to just load a straight 209 primer without the disc. However I will admit that I liked the disc. They were easy to load and use. And fit well right in my front pants or shirt pocket. very handy IMO.
The trigger on my LRH was great right out of the box.
I am going to try the Black Horn Powder in my LRH this week if I can get some. If not then I will use my heavy conical BP stand by load that is awesome at 200 yards.
You will not go wrong with the LRH. Maybe someone can tell us about the Mountaineer. Tom