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?

[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.