Slugs cracking during swaging

[Tomme boy]

I just started making more slugs. I mmm modified the top punch to give a rou d nose like the Brenneke slugs have. Trying to get a more weight forward slug.

They have been coming out great. But I was getting a little low in the casting pot. So I got out my lead that was from all sheet roofing lead. Added in 10lbs and a 1/2 bar of pewter in the small Lee bar mold. I had to add some tin the last time I filled the pot to get the Russian slugs to fill out.

Well now almost all of the slugs are cracking when I try to swage them. They are air cooled till the next day then sized. Most of the time they crack at the seam where the two halves meet. But sometimes they will fracture in multiple places.

What would cause this? It is the same lead I used before and did not have any cracks. These things seem really hard. Should I use a antimony mix instead of tin? Factory slugs are about using around 2%-3% antimony to make the lead flow easier during swaying and on impact

 

[Brad]

Antimony instead of tin.
You made the lead much less able to flow, antimony would do the opposite.

 

[CWLONGSHOT]

Need some more Rim Fire lead Tom?
CW

 

[RicinYakima]

Usually, it is too high percentage of antimony to tin. Sheet roofing lead is unknow scrap, so beware.

 

[Tomme boy]

When I processed this lead it was the worst I have done for the amount of lead oxides. It also seemed to have sulfer in it. There were some yellow oxides and a slight smell of sulfer. But it cleaned up fairly quick. I only had to flux one time.

Come to think of it, I had mixed the sheet lead with about 15 feet of 2" lead pipe on the last batch. That was what I have been using. It was casting bright shiny bullets and slugs. I am now thinking I might have thrown some of my lino ingot in with this. I was having a hard time keeping the mold hot enough to replace the slug and the slug not falling apart when it drops out of the mold.

@CWLONGSHOT pm me. I got some more brass I can trade. 300blk 10mm

 

[Tomme boy]

I may just stick with the Russian Botfly mold. I can cast 3x the slugs in the same time as this Lee mold cast. I have close to 150 of the Lee cast up and sized and powder coated right now. I am getting almost a 50% reject rate out of it. The Russian I get 1 or 2 per 100 rejects.

I went downstairs and the exact lead cast beautiful slugs.

 

[CWLONGSHOT]

I had terrible troubles with my LEE 1oz mold. Mostly it wouldn't drop Off the base pin. I took it apart and found major machine marks and a ledge on both sides. I polished it out as best I could without making it worse. I was able To cast a few hundred but the mold is toast. I gotta bad one I guess. Havent shot them yet.
I have a couple Savrog & FS molds and they do work real well! Havent loaded or shot any of those either.
PM comin Tom

CW

 

[Rally]

I had terrible troubles with my LEE 1oz mold. Mostly it wouldn't drop Off the base pin. I took it apart and found major machine marks and a ledge on both sides. I polished it out as best I could without making it worse. I was able To cast a few hundred but the mold is toast. I gotta bad one I guess. Havent shot them yet.
I have a couple Savrog & FS molds and they do work real well! Havent loaded or shot any of those either.
PM comin Tom

CW

I had the same troubles with both my 7/8 s slug moulds. I take the center pi’s out and buff them in my drill press with steel wool and synthetic two-cycle oil. Removes any burrs quite well.

 

[Tomme boy]

I made a new pin to get rid of the stupid cross bar. The only time it sticks now is if there is not enough heat in it.

 

[pcmacd]

I just started making more slugs. I mmm modified the top punch to give a rou d nose like the Brenneke slugs have. Trying to get a more weight forward slug.

They have been coming out great. But I was getting a little low in the casting pot. So I got out my lead that was from all sheet roofing lead. Added in 10lbs and a 1/2 bar of pewter in the small Lee bar mold. I had to add some tin the last time I filled the pot to get the Russian slugs to fill out.

Well now almost all of the slugs are cracking when I try to swage them. They are air cooled till the next day then sized. Most of the time they crack at the seam where the two halves meet. But sometimes they will fracture in multiple places.

What would cause this? It is the same lead I used before and did not have any cracks. These things seem really hard. Should I use a antimony mix instead of tin? Factory slugs are about using around 2%-3% antimony to make the lead flow easier during swaying and on impact

LEE specifically says to use 100% pure lead for their shotgun slug molds.

They make a REALLY BEEG DEAL ABOUT THIS!