I have one of the Cowboy LTD 24" rifles . Not sure the vintage or twist ( 1-38" I think ) but it is a JM . It will shoot clover leaf's all day long with most any load I have ever fed it . Any 250-270gr SWC with a stiff dose of Tite Group , Unique, Herco , or Red Dot will give excellent results in my rifle . I have dies by Lee, Redding , RCBS and Ideal 310 and a Tru Line set . Carbide or steel has never been an issue that I have noticed . I started with the steel 310 dies and a stamp pad with STP and changed to carbide when they got popular but other than not needing to lube each case I can't see a difference . My cases last as long now as they did 50 years ago .
Here's pictures. I know they kinda suck but I'm not a picture guy anyway .