Working on as cast diameter, new mold.

[mdi]

Well I worked out a problem (?) with my newest Ranch Dog mold (240 gr. RFNGC T/L). I'm sure most of youz guys have this figgered out, but I'm kinda hard headed! When it came in I cleaned it up and fired up the pot and cast a few, mebbe 80 (a six banger goes fast). Measured and weighed them. Too small (.431"). So I changed alloy to a harder lino based mix (WW to Lino, about 2-1). Still small and lighter this time. I needed some at least .432" to shoot in my Puma .44 carbine. Shut down and went inside to think about it. Checked my charts, yep lino or #2 should cast larger than wheel weights. Then AHA! cast cooler melt! Less shrinkage! So, I turned down my pot (on my Lee, just numbers, don't mean much, from 7.5 to a hair over 6). Mold came up to temp., cast a few, miked them. .433"! and less than .001" out of round. Measured 10 from various pours and had .001" to .0015" variation. Same alloy same method, different finished OD. Simple; cooler melt goes in mold, shrinks less 'cause it's cooler and "closer to solid" temp. and I get larger bullets.

Learn sumpin' evry day, ifin' ya use common sense...[smilie=w:

[Von Dingo]

Good statagy, thanks for the informaton

[geargnasher]

Now you understand why I harp on "100 degrees above full-liquidus" for alloy temperature. With Linotype, that's less than 575F!! With most clippy wheel weights, that's about 675. And guys who can't figure out how to get and keep their moulds up to casting temperature want to run the alloy at 750 or higher, then complain their boolits are too small.

Gear

[357shooter]

No doubt that harder likes cooler, or said the other way, softer likes hotter. At least in general. Some moulds have their own weird temp needs too.

Moulds for small bullets also like hotter alloy than moulds for bigger bullets. I'm talking 90gr vs 180gr. Small changes in bullet weight don't seem to matter much.

Since I don't cast bullets larger than 180, I would have to speculate that leven larger bullets w/alloy such as Lyman #2 would generally like pot temps quite a bit lower than BHN 8-9 & 125-180 grain bullets.

Added later: I forgot to add, I get the largest diameter bullets when the mould temp is not quite to frosting temp. Get close to frosting and cool it just a little for large diameter bullets. I rarely cast with anything as hard as WW and hardly ever with anything harder than that.

[41 mag fan]

Now you understand why I harp on "100 degrees above full-liquidus" for alloy temperature. With Linotype, that's less than 575F!! With most clippy wheel weights, that's about 675. And guys who can't figure out how to get and keep their moulds up to casting temperature want to run the alloy at 750 or higher, then complain their boolits are too small.

Gear

EXACTLY.... I followed your advice on 100degree over liquidous temp and found it it was spot on. With less shrinkage also comes right on weights of casts

[One Gun Andy]

Thanks for this valuable information. I like to do things as simply as possible, and a lower casting temp makes good sense.