I recalled back in my BPCR days that I added tin to get this effect, so that is what I did, since I have 14 one pound sticks of 50/50 solder.
19lb pure lead in one lb.ingots, and one stick of 50/50 solder, after a good fluxing should give me .01% Tin in the mix for a nice round, yet very soft ball.
Mmmm, let's see. 19 pounds of lead + 1 lb of 50% lead, 50% tin makes 19.5 lb lead with .5 lb. tin for 20 lb total.
.5 lb. / 20 lb. x 100% = 2.5% tin, so a bit harder than .01% tin. But if you can scratch it with your thumb nail, it should be soft enough! 
~Kees~
I wouldn't dare test an Engineer's math, but I did have my decimal out of place on that .01% mix.
I got that information from a post made by Glenn E.Fryxel a lot of years back, after I had worn out a dozen pencils trying to figure out a proper alloy for good fill-out, without added hardness.
Glen, a well respected writer in the field of cast bullets, once made the suggestion that "a bar of 50-50 fluxed well with 19# pure, should give a nice fill of around 0.1% Tin....now how he arrived at those figures I have no clue.
Still yet, I have used it ever since, especially when I have Minie Ball with a critical skirt, such as the Parker Hale type, and other loads where a good fill was necessary to get proper formed lube grooves.
Maven, I agree with what you said about the temperature, running that hot for any extended time will deplete the tin.
However, once again with Minies, and certain other unmentionable loads that are real heavy in weight, in fact, any bullet over 275/ 300gr, I like a high temperature to insure a good fill and a more constant weight. I feel that heat, with the extra weight of a bottom pour ladel, will push the air out filling the voids that are often seen when running too cold....you can't really see those voids, but by weighing they show their ugly face.
Pure Lead, plain round ball, up to .58 cal. I like to run mid-range 750*-850*, but for .62 and above I like the melt hot.
I am not even suggesting that hot is better for this purpose, but I am saying, after years of experience doing this very same thing, it simply works well for me.
Many who use bottom pour will likely have a disagreement with that statement, I realize and know that all to well, as it has been a favorite item of 'discussion' since I was knee-high to a Grasshopper, but I have stuck with it because that's what works for me.
I get a lot fewer throw-backs after weighing, when I do take the time to weigh...but I have to admit to weighing less with this method because the RB look and feel perfect....if I see, or even suspect a flaw, it's a really simple matter to put it back in the pot.
Has anyone tried the NEW Lee round ball molds yet?
They are much better vented, and have pin stops....the ball simply "falls" from the Mold.
I have always owned a few Lee Molds, along with most of the other popular brands, and I've never had a lot of problems with them...but the latest 3 I bought are billed as the "New Improved Model" and I've really taken a liken to them, like no other Mold I've ever owned.
I just wish I could get the old Lee "Trash Can" Mold in .50 cal in this new model Mold...that Mold was simply beyond reproach in a fast twist bbl....ugly as death, but outshot everything on the line. It performed really well, even in the 1:48.
I just know it would be great in 1:32 and maybe even better in a 1:26, and a 1:22 could well be "the cat's meow"...after all, it is ALL bearing surface...The Greenhill Formula agrees with that thinking, which makes me wonder how well practical application would turn out.
It's late night, and this "storm" we're having has not let up all day...Not a real storm, just a ugly storm, screwing things up with its constant sideways rain, damp, cold and miserable.
My friends on the 'other side' of the mountain all have web feet, guess web feet is going to be the new in-thing here in the Basin now.
Uncle Russ...
Topic: Really ugly day, but great for "runnin ball" / casting. (Read 1331 times)