Another casting session

[45-70 Chevroner]

I set down to cast some 155 gr. 7.62X39 boolits yesterday after noon. I have two single cavity Lee molds for that boolit ( 155 gr. Spire point with one lube grove). I am casting with WW and a little tin actually about two onces in a 20# Lee bottom pour pot. I got the pot up to 1000 degrees ( according to my Lyman thermometer) fluxed once droped it back to 800 + - 50 degrees. I cast about 200 boolits. I could tell that I was getting quite a few rejects at that temp. I was getting nice shiny boolits but with a lot of visiable defects. I cranked it back up to 1000 degree. I cast another 125 boolits that were a little frosted, by this time it was starting to get dark, so I quite for the evening.
I went out this evening and sorted them all out. Of the 200 shiny ones I had 100 boolits with more visiable defects than I like to see on my boolits. The 125 frosted ones all filled out nicely with one reject. The average weight of all the boolits was 160 gr. + or - .7 gr. and they were all measuring .313 to .314. Even the rejects were within that same range. I had 1 boolit that weighed a 154 grs. it had no defects. I know this is not rocket science but it worked for these two molds. As most of you know someting like this works this time but you never know what will happen on the next session.

[Ole]

Your alloy temp is way too hot.

My guess is either your mold has oil on it or is contaminated or you're trying to cast with too cold of a mold.

I cast with that mold around 700 degrees and it fills out fine.

What part of AZ are you in?

[noylj]

It's a Lee mold. It cools very fast. It is winter. It was probably cold where the OP was casting. Have nothing against frosted bullets--one step down from bullets with whiskers.
Never needed to get above 850 and almost always cast at 775-800 with aluminum molds. With an aluminum mold, I cast hot and fast or I stick the corner of the die in the melt to get up to temperature after cooling to drop the bullets. You HAVE to keep the mold hot--I don't know if you can get an aluminum mold too hot. Maybe a 6 cav mold?
The fact that it started to cast good frosty bullets indicates that the problem is not oil in the mold but a cold mold.

[NSP64]

The problem is he was using 2 molds in wintertime. The molds were cooling off. Next time try 1 mold and cast fast.

[45-70 Chevroner]

No oil in mold I have used them a number of times. The temp. in the garage was around 48 degrees. noylj and NSP64 are more than likely right. I did heat the molds by dipping the corner in the hot melt. As you get old your speed drops off some. I think I'm going to get a 2 cavity mold, or maybe even two. I am sure they will hold the temperature a little longer. By using two I can spend less time at the casting table and more time at the range.
When I bought those single cavity molds they didn't have the double cavity molds available.

[1Shirt]

45-70, Have reached the point in life where single cav molds with the exception of HP's and for big 45-70 blts are just a slow casting PIA. I cast as hot as I can get the pot, usually with 2 cav molds I run two at a time, and I water drop everything. Have gotten to really like the 6 cav. lee molds once you get them hot enough as well. I like my blts (regardless of rifle or handgun) to be a little frosty, as I agree with Paco Kelly that I think a bit of frosting holds/grips the lube a little better. As to the weights and variances, think that out of any batch of cast there will be a percentage that look perfect, but have in internal void and will weigh light. I also cast in my garage, and this time of year it is pretty cool out there, but I try to cast fast, and with a steady and consistant pace. Am also one of the true believers in Bullplate! Know this disagrees with the ideas/methods and thoughts of some others, but it works for me, and I have been casting for over 50 years. Good luck!
1Shirt!:coffee:

[Boolseye]

The 125 frosted ones all filled out nicely with one reject.
there's your answer. They were frosted 'cause the mold was very hot. The rejects happened when the mold was too cool. Dip the mold into the alloy for 15-20 seconds and cast fast. I don't mind the frosties either–they hold the tumble lube better. or so they say.