Lead alloy input sought

[R.W.Dale]

I'm looking for some input on my alloy. I am looking to cast rifle bullets to be powdercoated.

I have WW ingots and a kinda odd not quite Linotype alloy from "the bullet works" 2% Tin 8% antimony 90%Pb

What I'm trying to figure out is a good starting point for a mix ratio of this "good" but expensive alloy to cheap range lead and wheel weights. Most of the calculators I've found are based on Linotype which is a little stronger than what I have.

 

[grubbylabs]

Either Blarby on this forum, or the castboolits forum is your best source of info on that. I would shoot blarby a PM and visit the castboolits forum.

 

[clearcut]

I don't think the mix is so critical when you PC I water drop when I cast strait clip on ww and after I PC and it's working at 2400 fps in my .30-06.
CC

 

[R.W.Dale]

I don't think the mix is so critical when you PC I water drop when I cast strait clip on ww and after I PC and it's working at 2400 fps in my .30-06.
CC

How is accuracy?

It's my understanding that while PC prevents all leading associated with softer alloy for accuracy a certain hardness is still desirable to resist bullet distortion upon firing

 

[grubbylabs]

Their is quite an extensive thread on PCing bullets on the castboolits forum.

 

[rcmodel]

What are you going to be shooting them in?

I have used straight air-cooled WW alloy for .38, .44, & .45 bullets for about 55 years.

Getting them too hard is much worse then getting them too soft, unless you are loading for high-power rifle or very high pressure Magnum handguns.

rc

 

[Schwing]

How is accuracy?

It's my understanding that while PC prevents all leading associated with softer alloy for accuracy a certain hardness is still desirable to resist bullet distortion upon firing

This is correct. Powder coating will allow you to drive softer bullets hotter with no leading but will do NOTHING to improve accuracy. Adding gas checks seems to help some but not a huge amount where accuracy is concerned.

One overlooked part of powder coating is that, if you usually water drop your bullets straight from the mold, you will have to water drop them again after they come out of the oven from powder coating or any BHN gains from water dropping are cooked out. The other issue is that you do loose some hardness anyway because you don't powder coat at nearly the same temps that you cast so the post baking water drop will not have the same impact as the post cast water drop. Most people who powder coat overlook this but it is a factor.

I have done extensive powder coating testing and, in spite of everything I have read here, I have never achieved what I would consider good accuracy on higher pressure rounds on anything lower than about 18bhn. You can do a ballpark determination of how much pressure your alloy can handle by multiplying the BHN by 1400. In this case, your 18bhn alloy will not loose its elasticity until around 25,200psi... For lower pressure cartridges, this is fine but you will not be driving many rifle caliber cartridges over 1200-1300fps with this alloy.

I am not trying to talk you out of powder coating... i powder coat all of my bullets. What I am saying is, don't be fooled into thinking it will improve accuracy on cast bullets. Leading will disappear but accuracy is not going to deviate much from what you have seen before.

 

[grubbylabs]

I forgot. Blarby has a thread going on PCing bullets right here in this forum. Might be worth a read.

 

[243winxb]

WW can be heat treated as is. The other 2% Tin 8% antimony 90%Pb can be air cooled as is. Both will end up about the same hardness. No reason to mix them together. IMO.

 

[35 Whelen]

I thought PC-ing (I don't/won't do it) was the end-all, cure-all for leading. If this is the case, what's the point in water-dropping bullets to make them harder? Just curious...
35W

 

[tightgroup tiger]

If this is the case, what's the point in water-dropping bullets to make them harder? Just curious...

from RW Dale

How is accuracy?

It's my understanding that while PC prevents all leading associated with softer alloy for accuracy a certain hardness is still desirable to resist bullet distortion upon firing

 

[35 Whelen]

ALL lead and lead core bullets, that includes jacketed, distort to a degree upon being fired. Some more than other.

35W

 

[243winxb]

Cast bullets with soft lead. Powder Coatings

Cast bullets, when fired, can slump. Long nosed rifle bullets will bend off axis. Pistol bullets will compress showing smaller lube grooves. Stripping is another problem with very soft lead . I know little about PC, but this photo, showing a fired coated bullet, has exposed lead. http://www.pcimag.com/articles/the-effect-of-crosslinking-chemistry-on-superdurable-powder-coatings " Due to concerns with the toxicity of TGIC, powder coatings that contain more than 0.1% of the compound would have to carry a warning label that included the European Toxic label, which includes a skull and crossbones logo. The performance of TGIC in weathering is quite good, so this has significantly affected the use of the crosslinker in superdurable architectural coatings. If suitable replacements are found that can perform as well or better, they could be used to replace this compound. Clearly a need has developed in the European marketplace.

The United States does not yet have the same labeling requirement and there are no indications that a similar labeling requirement is imminent. However, most of the major powder coating producers operate globally and wish to have formulations that are universal. These requirements have encouraged North American producers to also look at alternatives to TGIC. " https://www.osha.gov/dts/chemicalsampling/data/CH_273775.html I can see where heat treated bullets may be annealed softer when baking the coating? So it looks like an air cooled bullet of the correct hardness is needed?

 

[jmorris]

. I know little about PC, but this photo, showing a fired coated bullet, has exposed lead.

There is a lot of surface area exposed on that bullet, the entire bottom of it is not coated.

 

[noylj]

I used 12-15 BHN and gas checks for velocities of 2200fps and up. If your coating holds up, then almost any alloy would work. Never had any 7mm or .30 caliber cast bullets slump or anything (or at least no crazy accuracy problems).
I would hope that nobody is breathing any powder coat powder components and don't see one cross-linking chemical all that worse than another.