Used my 45-70 mould today

[bigarm]

I got an RCBS 45-70 mould, 405 grain in a trade along with a 45-70 rifle. Wanted to try it today. Didn't have any RCBS handles so I took a Lee 6 cavity handle and ground down the bottom of it until it fit. Seemed to work okay. I then got to casting. Never have cast anything that big. Definitely was a learning curve involved. First ones were not so great. Lines in them and, for lack of better terms, feathers along the sides. Turned the heat up to about 730 and they seemed to come out better. Got some okay bullets that I think will work fine. Had to cut the sprue fairly quickly and then wait for some time to open the mould to get them to drop. I guess I am not that patient, because it seemed forever.

[happy7]

I would try running the mold hotter (not the pot, the mold). If you are cutting the sprue quickly on a bullet that big, then the mold is not hot enough, is my guess. 730 is plenty hot enough on the pot.

[bigarm]

Interesting. I had the mould on the hot plate on high. How would I get it hotter? Also, I weighed a couple quickly and they seemed to be heavy, about 425 instead of 405. I did it fast and did not calibrate the scale, so I could be wrong. Will try to remember to check them again tomorrow. I was using probably 75% coww and 25% soww, maybe a little closer to 50-50, but not quite.

[John Boy]

Had to cut the sprue fairly quickly and then wait for some time to open the mould to get them to drop.Heat the mold to the pot temperature so with a 5 second pour - the sprue puddle frosts in 5 seconds.
Would think if you had to wait for the bullets to drop - the mold was too hot and you have lead smear on top of the mold under the sprue plate

[happy7]

RCBS still makes their molds for Lyman #2 alloy which is lighter than straight COWW, and of course mixing in SOWW will make the bullet even heavier.

For preheating, stick a little piece of lead on the hotplate (hopefully it has a solid top). Gradually heat the hot plate till it just melts and then back off the heat till it no longer will melt. That will be a good setting for preheating your mold. If it won't melt lead, you probably need to find a different hot plate.

[bigarm]

Heat the mold to the pot temperature so with a 5 second pour - the sprue puddle frosts in 5 seconds.
Would think if you had to wait for the bullets to drop - the mold was too hot and you have lead smear on top of the mold under the sprue plate

The sprue cooled quickly and yes there is a lead smear on top of the mold under where the sprue plate goes. It was there already when I got the mold. How do I remove it? As I said, I did get bullets that seem ok after a few minutes. I will ask my wife to take pictures of them and then post the pictures. I have used the hot plate for all my casting before and the molds heated fine. I did notice that the light would go off quite often. It is from Wal-Mart, could be going out already I guess. It is only a few months old as I have only been casting since late summer.

[happy7]

good pictures would tell a lot. It sounds like if the bullets got better later in the casting session that the mold heated up giving you better bullets.

The smear on the top of the mold is very easy to clean. Get the mold hot and start casting. Use some bull plate lube or similar and lube the smears. Let is soak in for a few casts. Some of it should come off with a Q tip. If not, while the mold is full with bullets with well filled out bases (not when empty to protect the cavities) gently persuade the smear with use a little 0000 bronze or steel wool. You can be more agressive with the underside of the sprue plate. It smears when you cut the sprue too soon. If you keep the top of the mold covered with a very thin coat of bull plate lube, it will help greatly to prevent smears or at least make them not stick very well. But don't get too much lube. That will make for poorly filled out bases and also pitted bases.