Question about alloys and casting rifle boolits

[borg]

I have been casting forever,, pistol bullets, never rifle.
I bought a Lee 230 gr 30 cal, turned on the pot that was filled with I don't know what for pistol and started casting after prepping the moulds.
After about an hour of not getting any good boolits, still with wrinkles and still had a frosted look.
Begining to think the melt was mixed with too much zinc. As I put the bullets back in the pot, I noticed that they had
a pinging or ringing sound so concluded too much zinc,, they also weigh in the 223- 224 area. The dropped dia of them were @ .307-8, and were really hard to drop from the molds after smoking every other drop.
Would the zinc cause all the above, Like I said, I've casted forever for pistol which aren't as critical as for hardness for plinking.
Also, this my first aluminum molds, everything else I have are 6 and 8 cavity H&G & Saecos I've had 40 yrs.
Trying to get something to go through a 300 BLK.

[upnorthwis]

If it were me, I would shoot them to see how they work. That accomplishes two things: 1. You find out if they will shoot to your specifications rather than relying on theory. 2: You get rid of this alloy the fun way.

[bangerjim]

Why do you have ANY Zn in your mix? Granted up to 5% will not cause many problems.....just add more Sn to lower surface tension for good fill and NO WRINKLES. But most of us do not use Zn in our mixes........at least intensionally! They are dropping light, so that may mean a high concentration of Sb?

I have never cast above 5% Zn (for experiments only), so I do not have any input on your hard drops. You should not be smoking that mold like that! Mabe only ONCE when new. I do.....some don't.

BTW......wrinkles are most times caused by a cold mold or cold melt. A lack of Sn will also cause them. It is not your new mold, it is probably your temp or technique. You have been casting short boolits with no problems right? I have similar Lee 30 cal molds and the fill out 100% in a HOT mold and the right pot temp.....Bhn ~15 with ~2% Sn.

Do you heat your mold on an electric hotplate? Get it up to casting temp B4 you start and wrinkles will magically go away.

Play with the mold and pot temps. Let us know of your success.

Good luck!

banger

[borg]

I guess I was running too low a pot temp because the boolits were frosting, the pot started off about 700, frosted, dropped to 675.
This "lead" has been sitting in the pot for at least 15 yrs and is made up of ALL WW I could find at the time.
The mold were hot enough, melt was wrong and too cold, I will have to get some more WW and separate them this time.

Trying to be a COB, didn't work

[Tatume]

Low temperatures will not cause the highly desirable frosted appearance. Frosted bullets are good bullets, and the frosting indicates the temperature is a smidgeon above ideal temperature. Being above is good, being below is bad and causes voids and wrinkles. If you do not have an accurate way to track the temperature of your mold and your alloy, the safe way to cast good bullets is to run a little hot, which is indicated by frosting.

[bangerjim]

Yep........frosting means hot. I like frosty boolits because I PC them and it seems to stick a little better on those dull surfaces. As said, low temps of mold and alloy will cause your wrinlkes.

Best thing would be to dump that lead in your pot (save it for later mixing) and get a good know alloy for rifle boolits mixed up in there. Like I said I use ~15 for rifles with ~2% Sn + PC. They shoot excellent!

banger

[cbrick]

700 degrees is about perfect for casting WW and unless the mold is really hot won't cause wrinkles. Smoking the mold is a waste of time, yeah I know LEE says to do it. You just spent time getting it clean right? Why would the first thing you do with it is gunk it up and fill in the air vents. A clean mold is the best casting mold. It's possible the alloy is contaminated given both the weight and as cast diameter, it's also possible the mold casts small. With the frosted bullets make sure the mold isn't too hot, aluminum heats up very quickly. How is the fill-out other than small diameter? Try a different alloy and if they still cast small contact LEE & ask why, could possibly be a bad mold.

Rick

[borg]

All boolits have been wrinkled AND frosted @ 675 deg, even after casting and bringing the mold up to temp.
The thermometer I have is a mercury type originally used by a linotype setter and has been checked by my friends lab.

[dromia]

Any photographs?

[Down South]

I guess I was running too low a pot temp because the boolits were frosting, the pot started off about 700, frosted, dropped to 675.
This "lead" has been sitting in the pot for at least 15 yrs and is made up of ALL WW I could find at the time.
The mold were hot enough, melt was wrong and too cold, I will have to get some more WW and separate them this time.


Trying to be a COB, didn't work
I doubt that you have any Zn if the pot has been sitting that long. I don't think they had Zn WW out that long ago. Frosting comes from Higher temps, not lower.
You need to preheat your mould before casting or make several "15" cast and reject before keepers to bring the mould up to temp. You may need to add some tin to your alloy to get a better fill out. The right combination, Heat, Alloy, Tin will make a great fill out.

[Down South]

Any photographs?
Yes, Pics are worth a thousand words......

[borg]

I do know the molds are correct temp,, even after casting a SL of culls.
I stand by the temp of the melt.
They did have zinc back that long ago with the WW, still have some unmelted from that period.
I wish I could take a pic, but someone liked my camera more than I did, and none on my cheapie cell.
The casting pots I have are two OLD cast iron 20 # pots from Lyman I bought new.
I'm really not a noobie at casting, been doing it since the '60s.
Later today I will separate some of the WW I have without the zinc and try again.
Thanks for the input all.

[runfiverun]

That mold
gives me slightly frosted looking boolits no matter what I do
the bool it's come out well filled out with a melt temp of 700 or over
i was surprised at how oil free the mold was from lee it's got a slight taper to the boolit and only the bottom ring makes 310