Anatomy of a Cast Bullet

[Dieselhorses]

To Cull or not to Cull

I'm aware that there are several variables on the table when it comes to casting the "perfect" cast bullet. Most of you can confidently cast a thousand slugs and not second guess the results! Temperature, mold prep, mold quality, alloy, consistency and overall experience all play important roles in the outcome.

I've only been casting for 5 years and have acquired several molds as I cast for 11 other calibers. Some work wonders, some don't but in the essence of cast bullet quality- I've included a few pics just to subdue some opinions about useability. Bullets in question are Lee .356 124 RN. The following list is what I use:

Fluxed 50/50 WW/Pb
20:1 Tin
Lee 4-20 pot with PID set 730 degrees
Preheated Lee .356/124
Lube-Smoke's Powder Coat

I did roughly about an hour's research looking for a sticky or other posts related to this, if I missed a thread pls kindly post link! After casting nearly 1000 bullets I find that I'm culling about 200 +/-. The remaining 800 +/- were virtually flawless! Don't know if I'm just being too picky. I do know that a sharp, crisp full base and lube rings are important, but some bullets have random quirky lines which I know is probably a result of an intermittent pour. If the this is the case, does the lead bond ok? Will cast bullets separate at some point from muzzle to target?

308578
308579
308580
308581
308582
308583

[Wheelguns 1961]

I would cull all of those.

[Wheelguns 1961]

It is important to not get any lead in the cavity until you fill it. Can you easily see the spout and the sprue? Perhaps you need to raise your pot higher for a better view.

[Dusty Bannister]

I agree, those are all culls because with that much material missing they are at the minimum, out of balance. I freely admit that I am NOT in love with the TL style of bullets because slight variations in temp or tempo can result in a change in the diameter of the casting due to sluggish alloy. A nice simple Truncated cone is very easy to inspect for defects.

I suspect that the alloy was hot enough, but the ambient air temp was a bit cool, or a brisk cross draft, or you are thinking too much and not makin' bullets.

[JonB_in_Glencoe]

Cull 'em ALL !

[Calamity Jake]

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

[Bazoo]

I would cull them too.

But, I have shot some like that and didn’t notice a difference. The bottom one i’d cull for sure. The others I might let go depending on purpose.

I get better than 80% keepers. Closer to 90%. Sometimes as high as 95% When I tried to lube the mold with 2 cycle oil I got crappy bullets as the oil crept. I get much better results after switching to graphite.

One thing that will cause bullets like that is a spillover into an adjacent cavity. The little bit that cools before you finish your pour and move to the next will mimic a cold mold.

[JonB_in_Glencoe]

To Cull or not to Cull

>>>

After casting nearly 1000 bullets I find that I'm culling about 200 +/-. The remaining 800 +/- were virtually flawless! Don't know if I'm just being too picky. I do know that a sharp, crisp full base and lube rings are important, but some bullets have random quirky lines which I know is probably a result of an intermittent pour.

>>>SNIP
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?

[Walks]

I use the same mold myself in a 6cav. Preheated on a hotplate. I dump the 1st 3 pours and then start casting in company with another 4,5 or 6cav aluminum mold. Once I get the rhythm going I don't stop until the pot goes down to 1/3 full. Molds go back to hotplate and pot is refilled. I start over the same way, cast until my shoulders ache. Rhythm is key to consistent bullets.
And I cull hard, but only 3-4% . Rhythm is everything.

[fredj338]

I am not super picky for practice pistol bullets. I look for good bases & well filled out bullet. IF there is an odd anomaly in the nose, I dont sweat it. I cast hot, hot mold & add alloy when the 20# pot is 3/4 full, it keep casting time more consistent than filling a near empty pot. I do weigh my hunting bullets or my rifle bullets, but those are going out to 150y or so.

[Dieselhorses]

Good info, like really fast! Yea I guess wanted to see if I was the only caster who had rejects. Good rhythm, not overspilling into next cavity and ambient temp is what I'll work on. Also checking for burrs as this is a brand new 6 cavity mold. I can see the spout and sprue plate, but I stand while I'm casting (pot is on my Craftsman table saw) and could be elevated a bit. Yes, obviously all bullets in pics going back in melt.

[405grain]

Aside from the voids making the bullets imbalanced so that they won't fly straight, you'll also get gas blow-by with those bullets and that could cause barrel leading. Like others have indicated: it looks like a temperature related problem. It looks like some of the alloy is solidifying even before the mold is filled. You could be either filling the mold too slowly, using molds that are too cold, using alloy that's too cold, or the molds aren't venting air fast enough for the cavities to fill before the alloy starts to set. I would send those bullets back into the pot for a second chance. A word of caution; you want the pot of alloy to be hot, but not so HOT that it starts to oxidize. If you're casting small bullets in an aluminum mold, and have to wait until the sprue fully solidifies before dropping the bullets, the small bullets might not be sinking enough heat into the molds for good casting. That's a paradox; if you speed up the rate of casting to keep the mold blocks hot you might start getting lead smearing on the bottom of the sprue plate. If you keep having problems you might have to find a way to keep your molds hot. But do the simple stuff first - check to make sure that your molds air vent lines aren't clogged.

[The Dar]

I would try opening the valve on the 4-20 a little more, it could be that you're not pouring fast enough. Lot of good information from other members here already. Try changing one variable at a time. You'll get there.

[charlie b]

Everyone has rejects every now and then. How many depends on how good your process is.

I cast with one mold at a time. I control mold temp with a wet towel, touching either top or bottom or both depending on the mold.

In between I put the mold on a hot plate set such that the mold temp is higher than what I want. The first two pours are rejected, even if they look good, then the rest are usually good, visually.

For pistols they all get loaded and shot. For my rifle I go through a weight sort in 0.1gn batches. The bullets I keep are within 1gn of each other (165 and 210gn bullets). For 500 and 600yd (or target shooting) I only use the ones in the top half of the weight scale. The rest are used for shorter range, eg, soda cans at 300yds. I usually reject about 10-20% due to being underweight.

[Bigslug]

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.

[Winger Ed.]

Yep. They're goners.

I don't use any of that fancy scientific equipment, like a thermometer--
I run the heat up until I get a little frosting, then back it off just a little.
Lee says you can dip their molds in the pot to to heat them quicker.
That usually does it for me.

[dale2242]

Maybe I am too picky.
I only keep the visually perfect bullets.
That`s as far as go with handgun bullets.
All my rifle bullets are visually perfect and weighed.
I have been casting for 50+ years and have got the process pretty well figured out.
Don`t get me wrong, I`m still learning.
I find that I get the best fill out if I am getting just a slight frosting on my bullets.

[Castaway]

If casting rifle bullets I’m picky, pistol not so much, though I certainly would cull the pics you posted. I’m not a good enough pistol shot to tell the difference.

[JoeJames]

I'd cull them. One of many things I learned from the book "From Ingot to Target" was how to get the mold temp up fast. It said to invert the mold to where the sprue plate was on the bottom and then stick it partially into the melt to where the end of the sprue plate was in the melt itself. It sure made a difference in my casting. No more wrinkled bullets!

[popper]

Clean the mold! Oil will do that. Plus what others have said.

[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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308627 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.

[Walks]

I cast with multiple molds and like mold construction.
A pair of 6cav Lee's or a pair of 2cav RCBS. This keeps the mold at a fairly consistent temperature. About 700 degrees for iron/steel molds. And About 720 for aluminum.

I do use 2 cycle oil. Wipe it on, wait about 30 seconds and wipe off. It's hard to describe, but I do use brake cleaner before hot plate and after hot plate. Use with Extreme care spraying that stuff on a hot mold.

[charlie b]

I used to smoke molds a lot, mainly Lee 2 cavity. These days I don't. I have only Aluminum molds (Lee Accurate NOE). I clean them well with acetone when I get them. I 'lube' the sprue plate with a pencil. Just cover the bottom of the sprue plate with graphite. That's it. No brake cleaner, no 2stroke oil, nothing else. (I did lap one of my Lee molds to get it to case just a tad larger dia).

The key to casting is consistency at the 'proper' temperatures (pot and mold). Until you figure out what a mold likes, then write down what you are doing and cast 100. Record how long it took the sprue to solidify and what the bullets looked like. Then change something (eg, how long to wait between pour). Write it down. Cast some more. Change something. Write it down. Cast some more.

Learn to recognize symptoms. Wrinkles usually mean too cold. Not filled out base means sprue plate too cold, or, not enough sprue volume. Too frosty, too hot. Also, on long bullets, some localized shrinkage means too hot in the body section. Contamination will usually show up on the bullet surface.

Until I started keeping notes I didn't get anywhere. I'd change two things at once and then not know which one made a difference. I finally just sat and cast a bunch of bullets at different settings to see what would happen, recording each change. Three sessions (hundreds of bullets put back in the pot) and I got it down to what I wanted.

[Dieselhorses]

Again, great information from all of you. Finally looked at this one mold closely and noticed a few burrs at edges of ventilation cuts. More disappointing I discovered a “mar” of some sort at the too of one cavity. Guess I’ll be sending this one back. Didn’t really see any extra ridges on bases but…
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https://uploads.tapatalk-cdn.com/20230103/9b9d77f3c9a43162fc0b47f545599d67.jpg


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