Sharp edges

[semtav]

Currently trying to get a big batch of bullets cast up for my 45-90.
Using 20-1 alloy. 2 Molds I'm working with, a Steve Brooks micro groove 535 gr and a Bernie Rowles Brass mold @ 565 gr.

I'm having a hard time trying to get that sharp edge on all the lands. Most of my bullets have a rounded edge on a few of the lands. but not over the entire bullet.
The Bases are real sharp.

Casting @ 775 Deg starting with the mold held 90 deg then rotating upright as I pour then held for a couple seconds .

Using a Rowell ladle.

Looking at the bullets under a magnifying glass, they just aren't perfect, and I'm getting about a 3 gr spread in weight.

Any suggestions? Only thing I can think of is trying a batch of certified lead to see if its my alloy.

Thanks
Brian

[BABore]

You might try using an RCBS ladle and doing a pressure pour. That's alot of lead needed in a hurry without overloading the sprue hole. I always reach a certain point in diameter and length of a boolit where the Rowell no longer works as well. I'm assuming the mold is well cleaned and lightly smoked if it needs it.

[HORNET]

Yepper, try an RCBS or Lyman ladle. You might want to drill the hole out a little bit to let the alloy pour faster, check the size against the hole in the sprue plate. Mold at 90 degrees, spout in contact, roll mold horizontal, wait a couple seconds, roll the ladle back enough to get some melt flow out over the sprue plate to keep the sprue itself open so it can pull from the melt puddle as it cools & shrinks. Make sure ALL the vents are clear. Those big puppies take a couple of different tricks sometimes. (This from somebody that mostly casts .22's...)

[semtav]

Ordered an RCBS ladle. Will give it a try. for some reason, I thought I read somewhere that the rowell ladel had more pressure. Willing to try anything to see if it works.

Thanks
Brian

[Doc Highwall]

Take note of how fast you turn the mould/ladle from horizontal to upright as this affects how the air gets out of the mould and could cause some of your rounded edges. Try going slower giving the air a little more time to vent.

[montana_charlie]

Casting @ 775 Deg starting with the mold held 90 deg then rotating upright as I pour then held for a couple seconds .

Using a Rowell ladle.
I have a big Rowell for ingots, but have never used a small one for casting. I would like to try one, but I have always used the classic Lyman dipper.
However, I see no value in starting with the mould at ninety degrees when using the Rowell. It doesn't have the tubular spout which can be mated to a sprue plate hole, so I can't make it compute when considering a start with the mould on it's side.

Seems to me that, like the spout on a bottom feeder pot, you should just sneak up on the mould and start pouring down the hole. Like the bottom spout guys, you may get different results when pouring down the middle...or swirling it in from one side.

People talk about 'pressure pouring' but I don't believe it has anything to do with good bullets. I have tried it, and found nothing beneficial.

As for your fillout problem, I would get the mould a bit hotter to start...and cast with a rhythm which keeps it at the ideal temperature. (This assumes your vent lines are clear and your cavity is truly clean in the corners.)

I cast big bullets (in 20-1 alloy) at a 50 degree lower temperature than you, but your thermometer may read higher than 'actual'.
I know my Lyman does, because I checked it against a thermocouple. When the Lyman says 720 the thermocouple says 695.
I cast at 725 as read from the thermocouple.

[XWrench3]

this will probably show my casting inexperience, but what the heck. have you tried adding extra tin or linotype to the mix? that always helps me.

[montana_charlie]

this will probably show my casting inexperience, but what the heck. have you tried adding extra tin or linotype to the mix? that always helps me.
Linotype makes for hard bullets.
When adding tin to (say) w/w to aid in fillout, it's tough to get the caster to spring for more than 2% tin in the mix.

20-1 alloy is a popular metal for soft cast bullets used in black powder rifle cartridges.
It contains only lead and tin, and the tin content is 5%.
CM

[257 Shooter]

CM, Great reply!

[semtav]

Well, I know when I was getting poor bases, I kept it flat and poured from an inch up and it helped with the bases. I'll keep trying a few more things while I wait for my RCBS ladle.

thanks
Brian

[Doc Highwall]

semtav, poor base fill out could be a sprue plate that is too tight. I had that trouble with a mould and I used a fine stone to put about a .003" max edge break on the two mould halves along with loosing the sprue plate eliminated the problem.

[semtav]

semtav, poor base fill out could be a sprue plate that is too tight. I had that trouble with a mould and I used a fine stone to put about a .003" max edge break on the two mould halves along with loosing the sprue plate eliminated the problem.

Yea ,thanks Doc, I did loosen my plate up and am getting good bases now. Its just the edges of the lands I'm still having trouble with.

My problem with the loose plate, is I like to pour from the end of the mold, and the plate kept slipping open just a tad. finally had to learn to pour from the side of the mold to stop that. (pouring with the mold and dipper parallel to each other as opposed to having them at 90 deg to each other.)

[AZ-Stew]

Don't make the sprue plate too lose or you'll get a base that's sharp, but out of square with the boolit axis.

A bit more tin may help with fillout, but if you're only getting 3 grains variance on a 560 grain boolit, it's only 1/2 of one percent (.005 of total weight). That's not bad.

Regards,

Stew

[Dan Cash]

1. Get your RCBS dippeer.
2. Drill the pour hole to 3/16
3. Preheat your mold more. 60 seconds top and 60 bottom on burner flame.
4. Dial up the heat on your melt.
5. Get a second mold in operation, when one is full, set it down and pour the other. Makes a good rythm and your weight varriance will go down to less than a grain.

[BrianB]

Just curious...a 3 grain spread in weight? Percentage-wise, what is that? You're throwing a huge chunk of lead. Personally, I would just go shoot some of them before I made changes.

I'll bet those bullets are better shooters than I am.

Let us know what happens at the range, I'm really interested to hear about the accurracy of the the 3 grain spread bullets.

[montana_charlie]

I did loosen my plate up and am getting good bases now. Its just the edges of the lands I'm still having trouble with.
The thing with sprue plate adjustment is...if it's too loose it can allow bases which are not absolutely flat; and if it's too tight it hampers airflow between the plate and top of the blocks.

There is a spring washer on the pivot screw. Adjust the screw so that the plate is held flat to the blocks under spring tension, but you can lift the plate with your finger. As long as the plate has room for vertical movement, the hot air will force it's way out...IF you are not bearing down hard on it with the dipper.

As for your rounded driving bands...
How many seconds pass between the point where you begin one pour, do all of your 'rhythm stuff', and then begin the next one?

CM

[geargnasher]

Mould too cool is the main problem, you need to either preheat periodically on an electric hot plate or gas burner (as often as necessary) or cast MUCH faster than you're doing. Minimum three pours a minute to keep that mould hot, and that's once it IS hot. Aluminum and brass moulds have extremely high thermal conductivity compared to iron and they lose heat to the air very quickly. Even very hot lead will shy away from the corners of a too-cool mould.

20:1 takes a little more heat than WW, but 700* ought to be plenty IF THE MOULD IS HOT ENOUGH. I would keep the mould at 400-450*.

Watch pressure casting even with a rowel because it can force lead into the vent lines and clog them up, making you cuss and have to stop and clean them out carefully.

Gear

[montana_charlie]

Minimum three pours a minute to keep that mould hot, and that's once it IS hot. Aluminum and brass moulds have extremely high thermal conductivity compared to iron and they lose heat to the air very quickly.
The Brooks mould he is using is iron.

[semtav]

Thanks for all the replies. don't have a clock with a second hand, but I'll get one and time it. gonna try a bunch of different speeds, temps, ladles etc to see if I can find one that is consistent. Wind is howling so I don't have much else to do.

The ones I've shot ( sorted to 1 grain) shot good considering a 30 mph wind.

I'm not too worried about the 3 gr for shorter distance, but for 1000 yds, as long as I'm trying to get everything else as close to exact as I can, I just as well have my bullets the same.

Brian

[67bear]

I cast 20-1 with a .458 Paul Jones 535 grain creedmore bullet mould and I had to raise the temp to 820 degrees to fill out the bullet properly. Measured the temp with a Lyman thermometer and poured them with a lyman ladle with the spout opened up a bit.

[RICKLANDES]

You need more heat in the mold and more lead into the mold. I bottom pour and allow the lead flow to continue a bit after the sprue is filled. If you watch closely the lead will appear to stop and flow again into the mold before the sprue reforms. (If you weld the term wetting out will give a better mental image of what I am trying to share.) The lead in the tip begins to cool before the top of the mold is completely filled with lead (or emptied of air). There is overflow, but very few are under weight. I then weigh mine into weight catergories. Most fall into a fractional grain plus of minus.

I am beleiving you are fluxing a couple of times before pouring also. Maralux has materials that assist with the smoothness of your finished boolit. I will flux a batch about three times before I pour. Stir it in very well.

[semtav]

Cast about 70 and getting much better fills. Tried to get the mold a little hotter without getting the sprue plate too hot. ( about 40 seconds per bullet.) Still using the rowell, but waitng for the RCBS ladle.

Still getting about 3 gr variation, but if I get rid of the first half dozen, they are closer to 1.5 gr variation.

Thanks
Brian

[montana_charlie]

Cast about 70 and getting much better fills. Tried to get the mold a little hotter without getting the sprue plate too hot.
A hotter mould should be on the right track.
Why are you worried about the sprue plate?
40 to 50 seconds per bullet sounds about right.

CM

[DMCasts]

I've dipped/poured out of a ladle with a 1/8 inch hole drilled in the bottom of that ladle trickeling the lead into mold w/ great results.

[DMCasts]

uhmm,, maybe a little smaller hole to start with.

[semtav]

A hotter mould should be on the right track.
Why are you worried about the sprue plate?
40 to 50 seconds per bullet sounds about right.

CM

Guess I figured when the sprue wouldn't puddle, but ran of in a thin sheen, it was too hot, so I try to keep it cool enough to make the sprue puddle a little. Plus it keeps from getting that smear of lead on the underside.