=I am getting a TC Renegade with a Green Mountain 50 caliber fast twist barrel for an elk hunt this fall. I have a maxi ball 50 caliber mold. I believe it will cast about a 370 grain bullet but I haven't weighed any yet. My question is what lead hardness should I use for elk. Pure lead or lead with a little tin, such as 20-1 or 30-1 ? For a harder bullet for more penetration on elk.
You will have no issue with penetration with a Maxi Ball on Elk regardless.
In terms of a 370 grain, .50 caliber Maxi Ball, the accuracy is, or should be, very good out to at least 100 to 125 yards.
In terms of sealing the bore with the band as the Maxi Ball is loaded, a little softer lead will help.
One way that a person can find out, or use as a guide, is to purchase one box Maxi Balls and compare those to whatever lead you may want to try. You could also melt down a couple of the purchased Maxi Balls and remold them with your mold just to ascertain everything is acceptable to you and your particular ML.
The last Maxi Balls I molded was made from melted down Hornady GPB as a test. Those are made from some pretty soft lead. In my particular ML, they loaded easy and were accurate. Being solid lead with no hollow cavities, I wouldn't hesitate to use them on elk.
I have killed quite a few deer and one elk with hand casted .50 caliber Maxi Balls that were made from much harder lead than I like. They penetrate very well and were fairly accurate. However, they will be melted back down into ingots for fishing sinkers. I'll be using softer lead in the future.