Newbie question on slug casting - sprue cutting

[airgunfans]

After some success with casting pure lead, I just attempted to cast with 9:1 lead : linotype alloy. The difference is huge. The sprue will drop out by itself instead of sticking to the spure plate like lead. However, it seems that the metal is a LOT more brittle as the sprues would break some times when it hit the steel tray for collecting them. Is that normal ? 

The most annoying thing is that I can no longer get a smooth cut. With lead, the cut is very smooth as can be seen in the photo below. With alloy, there a a lot of cracks in the cut like what's seen when a piece of metal is repetitively bent and ultimately breaks because of fatigue. I got some metal sticking above the cutting plane causing the magazine to be jammed some time. The length of the slug is just equal to that of the magazine so there is very little tolerance. May I have some advices on how to get a smoother cut pls ? Is it possible that I did not get linotype but some other kinds of metals ? ? Thanks in advance. 

 

[oldsparky]

You may need to run the Lino hotter than pure lead. I have never cast small bullets. Do you have a hard time keeping a small caliber mold hot? I am curious about casting for air rifles. I have a lot of casting equipment for larger stuff. but have never cast under 38 cal. Is there anything beneficial casting an alloy when shooting low velocity?



thanks

 

[airgunfans]

Is there anything beneficial casting an alloy when shooting low velocity?

My rifle ( a .22 cal Huben K1 ) has got a chocked barrel. I have been told that pure-lead slugs will deposite lead in the barrel more quickly and more frequent cleaning will be needed. 

 

[marflow]

so I think it is too much linotype, that should be 4-5% with 2% tin the rest pure lead

everyone has there own recipe but the linotype make the blend too hard if you use too much

 

[leadfoot]

A harder than lead alloy is only needed for higher velocity bullets. A hard alloy does not necessarily mean less lead is deposited in the bore, it could be just the opposite. If your mold is specifically designed for airgun use, what does the manufacturer recommend? 

 

[badammo]

You may not be letting the mold cool long enough before hitting the sprue plate. A little A little trial and error of how long to wait maybe 30 seconds of so. Drop bullets on a towel as they are easily damaged when hot.

 

[oldsparky]

I may be wrong, but the sprue looks like it's broke off not smeared. Like when the lead has not cooled enough and you cut the sprue.