Dixie sells the Investarms .54 Hawken that's from the same maker as the Lyman guns.
It has a 1 in 48" twist, ~29" barrel, double triggers, an adjustable rear sight and a Monte Carlo cheekpiece. It's a very comfortable gun that's an exact clone of the Cabela's .50 Hawken.
Look at a Cabela's Hawken. It has the Investarms logo on it.