Anatomy of a Cast Bullet

[slim1836]

I have a mold from a well known mold maker that I tried everything on to achieve decent results with no results, until I smoked it. I do not like to smoke a mold, but I was at wits end on this one. I had cleaned it until I just gave up and smoking gave me instant results. It's the only mold I have smoked. YMMV.

Slim

[Dieselhorses]

Have you noticed that while you are casting, and get into the groove of things, that all the boolits drop near perfect?

What I do for pistol boolits, when that groove starts, I push all the previous cast boolits aside and just remelt them. Then continue casting until things go less than perfect or the pot is near empty. I find I don't need to sort/cull the batch...saves time, unless you like to sort them?

Yes, that's exactly the scenario. There was a period (about an hour plus) in between where it was like "clockwork". Just have to work on finding that "nitch" at the start!

[Dieselhorses]

There's 2 reasons for the voids you have, 1 mold temp and or 2 a venting problem.
Check vent lines adjacent to the cavities, look for burs closing the vents.
pre heat mold on a hot plate while casting pot is coming to temp.
if possible loosen the spru plate a little to allow air to escape

One thing I didn't mention and when you mentioned something about "burrs" it got me thinking that maybe that's why cavity 3 of six was sticking. Always took a few extra taps to get that one out. Inspecting mold today.

[Dieselhorses]

IME, you're running too cold by probably 40-60 degrees in the melt, and maybe need to work a little quicker to get the mold hotter. At the point you're running with sharp fillout and frosty bullets, you can think about backing down. It'll vary a bit from mold to mold, but you should have everything warm enough to where your sprues take maybe ten seconds after the pour finishes to freeze and change color.

What is the perfect melt temp? I know it depends on the alloy and/or mold type but at 730 and if I add 40-60 then it's bringing me close to 800. It was taking roughly 10 seconds to cut sprues off with no smearing at 730.

[slughammer]

I run the heat up until I get a little frosting, then back it off just a little.

I run the heat up until I get a little frosting and then I leave it there. I'd rather cast 800 frosty boolits that are well filled out, than have to sort pistol boolits. It's WAY faster to cast slower and not sort, than it is to cast fast then sort and cull.

My only issue is getting the mold too hot and it takes too long for the sprue to cool or risk smearing. For years I used a small desk fan and a block of wood. The mold hides behind the block of wood and the fan blows over the sprue.

When I say sprue, that's singular. Even for a Lee 6 cavity I pour each cavity and pull slowly to the next. I'm only filling 1 cavity at a time, but I end up with a 1 piece sprue.

Also, I use a clock with a second hand. Shearing the sprue either every 30 or 20 seconds depending on how long its taking for the sprue to harden.

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[Dieselhorses]

I run the heat up until I get a little frosting and then I leave it there. I'd rather cast 800 frosty boolits that are well filled out, than have to sort pistol boolits. It's WAY faster to cast slower and not sort, than it is to cast fast then sort and cull.

My only issue is getting the mold too hot and it takes too long for the sprue to cool or risk smearing. For years I used a small desk fan and a block of wood. The mold hides behind the block of wood and the fan blows over the sprue.

When I say sprue, that's singular. Even for a Lee 6 cavity I pour each cavity and pull slowly to the next. I'm only filling 1 cavity at a time, but I end up with a 1 piece sprue.

Also, I use a clock with a second hand. Shearing the sprue either every 30 or 20 seconds depending on how long its taking for the sprue to harden.

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Great information. (Have to find my instructions from Hatch for PID!)

[41mag]

I load and shoot a lot of similar bullets to what you have there. With them and even with all the other types I have some that for whatever reason end up like the ones pictured.

I cull almost all of them that have any sort of line or groove up the sides. Little wrinkles on the round nose, not a deal killer for batch blasting ammo. Most of that is simply for trigger time, or grandkids anyway. Most of those ugly ones get powder coated and after they look just fine. The lines up the sides however, even full of the coating, make me wonder.

For the hunting bullets in either rifle or handgun, I'm a bit more anal and like some go so far as to weight sort. Not that a hog or deer could tell the difference, I just prefer knowing each shot should be the same as the next or last one. Most all of these are conventional lubed and I want as close to perfect as I can manage.

[justindad]

A few rules of thumb for culling that I use:
1) The corners of the driving bands should not be radiused/round so severely that half of the driving band will not touch the barrel.
2) The must not be any voids that span the length of a single driving band.
3) Voids must not result is any sharp corners or other geometry that looks like it could be a fracture point.
4) The base should not have any visible radius.
5) There should not be any defects or voids where the case mouth is crimped into the boolit.
6) No inclusions allowed on driving bands.
7) Sprue cut should be flat, so the boolit can stand up straight while being sized.
8) Frosting cannot be so severe that geometric features are washed out.

[BNE]

Agree with others that you should go hotter. Also. Some of those lines at the tip are possibly due to the drip of lead on your spout. It can be cooler than the melt and solidify first.

I get around this by starting the pour on the spruce plate and moving the mold into the stream. This helps keep the sprue hot also.

I would full the ones you showed also, but they probably would shoot just fine at pistol distances.

[JonB_in_Glencoe]

What is the perfect melt temp? I know it depends on the alloy and/or mold type but at 730 and if I add 40-60 then it's bringing me close to 800. It was taking roughly 10 seconds to cut sprues off with no smearing at 730.

Mold temp is MUCH more important than alloy temp.
typically, the alloy temp should be about 100º higher than the alloy's liquidus temp.
Pure Lead's liquidus temp is 621º and COWW alloy's liquidus temp is just over 500º, so ideally you should be able to set you furnace to just over 600º for COWW. For bottom pour pot users, it's a wee bit higher (like 60º to 75º higher) because of where the temp probe is, compared to the location where the alloy enters the mold (it cools off some during that journey).

I judge Mold temp by the color/finish of the dropped boolits. If the boolits are shiny, the mold is too cold. If they are heavily frosted looking, then the mold is too hot. I like a uniform dull grey, lightly frosted look.

You change the mold temp by casting at a faster pace...and cooling the mold, the opposite (slower place). I will also add, that every mold seems to want something different, so it pays to takes notes.
Good Luck.

[JonB_in_Glencoe]

Yes, that's exactly the scenario. There was a period (about an hour plus) in between where it was like "clockwork". Just have to work on finding that "nitch" at the start!

So, one of the things that was a "Game changer" for me, as far as getting into the nitch/groove as soon as possible, is using a Hotplate (mold oven) to preheat the mold to the correct temp, which is around 375 to 400, if you have a way to measure temp.
Good Luck.

[ascast]

good stuff, but are you using a 1 cav or 6 cav? Are your bad bullets coming from the ends or middle? Ladle or bottom spout? Maybe your end cavs are cooling off a bit more between pours. Just trowing that on the pile. It looks like a temp issue to me. keep at it, you'll get it.

[Dieselhorses]

good stuff, but are you using a 1 cav or 6 cav? Are your bad bullets coming from the ends or middle? Ladle or bottom spout? Maybe your end cavs are cooling off a bit more between pours. Just trowing that on the pile. It looks like a temp issue to me. keep at it, you'll get it.

On a good day I can pour each cavity in about a second without any partial fill to next cavity. (Yes-6 cavity mold). I’m left with about 1/4” wide sprue spanning all six cavities. About 10 seconds go by and I cut sprue. Wasn’t really paying attention where bad bullets were coming from but will inspect mold today. I know it’s me and not mold most likely. Going to bypass the PID and just use temp probe to get about 760-780 degrees and find that “slightly frosted” look.


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[Rockindaddy]

Hey Diesel:
You are a boolit master! I have shot and recovered wrinkle boolits !! They seem to shoot OK They don't look so good though. I have developed some good mould habits over the years. The best moulds are Lyman, Magma, H&G, RCBS, and Saeco. Have a few aluminum Lee blocks too. To keep them from rusting, you oil them. That oil is a problem when you go to use the mould. Brake cleaner really degreases the blocks. Keeping a cast boolit and sprue in the mould helps preserve the cavity. Preheating the mould before pouring lead aids in producing good projectiles. Started using ZEP spray graphite on my moulds since buying a Magma Master Caster! Bullets are perfect. The spray ZEP graphite keeps the sprue plate from dragging on the mould block tops. Try the degrease, spray with graphite, and preheat and your boolits will look like they were cast by a Boolit Master !!!!!

[Four-Sixty]

I'm curious Dieselhorses, do you lube your sprue plate while casting? If so, what do you use and how do you apply the lube?

[Dieselhorses]

I'm curious Dieselhorses, do you lube your sprue plate while casting? If so, what do you use and how do you apply the lube?

Yes I do, use 2 cycle oil or bees wax when I can find it. I make sure none gets close to cavities.


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[Dieselhorses]

Hey Diesel:
You are a boolit master! I have shot and recovered wrinkle boolits !! They seem to shoot OK They don't look so good though. I have developed some good mould habits over the years. The best moulds are Lyman, Magma, H&G, RCBS, and Saeco. Have a few aluminum Lee blocks too. To keep them from rusting, you oil them. That oil is a problem when you go to use the mould. Brake cleaner really degreases the blocks. Keeping a cast boolit and sprue in the mould helps preserve the cavity. Preheating the mould before pouring lead aids in producing good projectiles. Started using ZEP spray graphite on my moulds since buying a Magma Master Caster! Bullets are perfect. The spray ZEP graphite keeps the sprue plate from dragging on the mould block tops. Try the degrease, spray with graphite, and preheat and your boolits will look like they were cast by a Boolit Master !!!!!

Did clean with brake cleaner and swabbed and dried the entire mold. Gonna have to try that Zep!


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[Dieselhorses]

Casting bullets is an art, a profession and a perishable skill. Most on this forum has mastered this skill and probably knows their molds about as good as they do their spouses!

Please add anything else if you will as this could be useful to newbies and could save them from asking the same thing.

One other oddity I found is with the Lee 4-20, the nozzle wants to clog now and then. Now every time I store pot, even if just for the night, I clean the nozzle and port on inside. Anyway I keep a Bic lighter close by and heat nozzle a few seconds and that opens it up. Maybe this is a sign I need a hotter melt?


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[Dusty Bannister]

The Lee 4-20 had the nozzle located in the middle of the bottom of the pot. The heating elements are about mid way between the top and bottom of the pot. Heat rises, the nozzle is exposed to cool air. It is not necessarily dirt you are clearing from the nozzle but more likely some metal. Added excessive copper is noted for this issue. Not knowing the temp of the alloy or the ambient air temp or even a cross ventilation it is hard to say you "just need to increase the melt temp".

[Wheelguns 1961]

The nozzle on my 4-20 starts flowing freely at around 685 degrees. For non hp aluminum molds, I usually set my PID to 730 degrees. For brass hp molds, I am usually between 750-775, depending on the bullet size.