Solution for flashing on rifle bullets?

[Michael J. Spangler]

I know the best fix is a properly adjusted mould.
However I find the best filled out and most consistent bullets drop from my Lyman 457132 using about a 700 degree alloy of 50/50 COWW and Pure with some added tin and the use of a label to "pressure pour" I know the heat convinced with the alloy having a lower surface tension and the ladle can make the alloy want to seep into any nook and cranny of a mould.

So I could play with a lower alloy temp and a faster cadence but that always gives me frosted bullets.

Having said all of that I end up with some flashing on the bullet bases from time to time and though up a remedy. I don't know if it's any good or if it's been done.

After peeling off any flash possible with my nail I ran the base of these bullets into the lee chamfer tool.
https://leeprecision.com/chamfer-tool.html
I just broke the edge a few thousandths and any remaining flashing flaked right off. This may not give me the most consistent bullet bases but I would think it's an improvement over some folded over bits of flashing.
In hindsight I think I would have done this operation before sizing, especially because these bullets are being sized down from as cast about .459" down to .453" for paper patching. The relatively large drop in diameter might flatten out the base and leave it with almost zero bevel.

Anyway what are your thoughts? Have you done this? Will you give it a try?
I'm going to grab a new chamfer tool from my local shop this week (stocking Lee dealer with all of the items they sell including moulds) because my old one is a little beat up and I'm guessing a nice new sharp one would cut a little nicer.

[Winger Ed.]

When that happens to me, and I know the mold is closing right-
either using more pure lead in the alloy, and/or backing off the temperature a tiny bit fixed it.

[Michael J. Spangler]

When that happens to me, and I know the mold is closing right-
either using more pure lead in the alloy, and/or backing off the temperature a tiny bit fixed it.

That usually works but then I have less than perfect fill out on this big old 535 grain bullet.

[WRideout]

I know the best fix is a properly adjusted mould.
However I find the best filled out and most consistent bullets drop from my Lyman 457132 using about a 700 degree alloy of 50/50 COWW and Pure with some added tin and the use of a label to "pressure pour" I know the heat convinced with the alloy having a lower surface tension and the ladle can make the alloy want to seep into any nook and cranny of a mould.

So I could play with a lower alloy temp and a faster cadence but that always gives me frosted bullets.

Having said all of that I end up with some flashing on the bullet bases from time to time and though up a remedy. I don't know if it's any good or if it's been done.

After peeling off any flash possible with my nail I ran the base of these bullets into the lee chamfer tool.
https://leeprecision.com/chamfer-tool.html
I just broke the edge a few thousandths and any remaining flashing flaked right off. This may not give me the most consistent bullet bases but I would think it's an improvement over some folded over bits of flashing.
In hindsight I think I would have done this operation before sizing, especially because these bullets are being sized down from as cast about .459" down to .453" for paper patching. The relatively large drop in diameter might flatten out the base and leave it with almost zero bevel.

Anyway what are your thoughts? Have you done this? Will you give it a try?
I'm going to grab a new chamfer tool from my local shop this week (stocking Lee dealer with all of the items they sell including moulds) because my old one is a little beat up and I'm guessing a nice new sharp one would cut a little nicer.

Frosted boolits are not a problem beyond appearance, and they shoot fine. When I have that problem, it usually means the sprue cutter plate is not flat to the top of the mold.

Wayne

[Michael J. Spangler]

Frosted boolits are not a problem beyond appearance, and they shoot fine. When I have that problem, it usually means the sprue cutter plate is not flat to the top of the mold.

Wayne

As stated I don’t have issues with this mould with a less rich alloy or with a lower temp.
I think it’s more of the heat and alloy. Like when you pressure cast and can even get alloy to flow into vent lines.

Either way the thread was more about a solution to bullets that have flashing on the bases after the fact.
I also stated that I know the best solution is to get the mould running without any flashing to begin with and that it’s more of an issue of the alloy and heat causing it but the alloy and heat being necessary to a perfect casting.

[Peregrine]

I'm struggling with this myself on one of my moulds. :(

[Michael J. Spangler]

I'm struggling with this myself on one of my moulds. :(

Might be worth trying this.
Or if you can use a lower tin alloy or higher antimony to up the surface tension without ruining how the mould fills out.
It’s a balancing act with these big bullets.

[Springfield]

Do you lube the sprue plate face with Bullshop type lube? That always helps me a bit. Some of my LEE 6 cavs have tens of thousands of bullets cast with them and they just don't fit as well as they used to, but for SASS type shooting I don't sweat it.

[samari46]

You could open up the sprue hole on the sprue plate to avoid having to use the pressure casting. And open the hole in your ladle if your having problems with mold fill out. I use a center bit such as used in a lathe as I have a few older ones that don't cut as well. And you could lap the sprue plate on the mold side. You'd be surprised how flat they aren't. Frank

[Wayne Smith]

What's the problem? If you are sizing them down that much the flashing is long gone. Yeah, I'd rub as much off as I can, but not worry.

[Michael J. Spangler]

What's the problem? If you are sizing them down that much the flashing is long gone. Yeah, I'd rub as much off as I can, but not worry.

I’m just trying to show another fix for flashing issues.
I should have worded the title better because everyone thinks I’m looking for a fix. I’m giving a possible fix that’s all.

[beagle]

I've run a bunch of them and encountered the same problem. Now, this is not a flip answer but your mould blocks are too hot. The problem with the Lyman moulds is their small iron blocks for the big bullets don't dissipate heat fast enough for you to cast at your normal casting tempo. Lot of temperature going into those small blocks with each pour. I slowed my casting tempo down and it went away. I even went so far as to make a casting shelf with a small squirrel cage fan mounted under a screen mesh that I set my moulds on while cooling. This helped some. We even experimented with mounting serrated aluminum cooling blocks and this worked to dissipate the heat but made the blocks cumbersome to cast with. I'll bet an aluminum mould of that design would also eliminate the problem as they bleed off heat like crazy./beagle

[winelover]

I ladle cast. When I get occasional flashing on the base, the sprew plate is out of adjustment. Sometimes, the adjusting screw loosens. Another cause, is that a fleck of lead, slightly raises the plate. Check/clean bottom of plate and add lube.

Winelover

[Sig556r]

Not sure if beveling the base with a chamfer tool to get rid of flashing is an optimum idea, especially sizing down quite a bit from .459 to .453. I'd rather size them upside down & that should take care of any flashing. You may not want lead shavings or worse, dust collecting around the bench. As others have mentioned, flashing may indicate uneven contact surface between mold & sprue plate.

[mdi]

Have you tried not "pressure pouring"? I have a few molds that do the same ("flashing") when I used a ladle and pressure poured. My fix? Don't pressure pour. I got/get good fill out which I control with temperatures, with all my alloys from my "mystery metal", to range scrap, my handgun bullet alloy (BHN 12), Lyman #2 and on the rare occasions when I use it, linotype...

[Peregrine]

I've really been struggling with rounded bases as well, despite playing with temperature and loosening my sprue plates so they sing freely. A fairly heavy pour pressure is the only thing I have going to mitigate those.

[winelover]

Never had to pressure pour, when ladle casting, to avoid rounded bases. Providing a big enough (hammer)ladle is used. I routinely use a #2 Rowell ladle...........provides enough alloy, as well as pouring heat. Rounded bases are the result of mould not getting enough alloy, from the sprew puddle. And/or the mould isn't up to the right temperature. Flooding the mould with enough molten alloy will get and keep a mould up to the right casting temperature.

Winelover

[mdi]

I believe the finning, in my experience, is due to the "pressure pour". I would address the rounded bases/fillout as a separate "problem". I can only share my experience; pressure pour equals finning. Rounded bottoms/fillout can be worked out with temperature changes (both mold and alloy), alloy and methods.

[centershot]

I ladle cast. When I get occasional flashing on the base, the sprew plate is out of adjustment. Sometimes, the adjusting screw loosens. Another cause, is that a fleck of lead, slightly raises the plate. Check/clean bottom of plate and add lube.

Winelover

Bingo!!! Give this man a cigar!!! Every single time I see flash on my bases, it's because the sprue plate screw is out of adjustment! Never fails!