Common Alloys And Their Uses

[fiver]

antimonial growth is an odd thing.
I have seen it and I haven't seen it happen with the same alloy, and with molds from the same company that have quite similar shapes.
can it be tracked back to part of the process, or the air temp, or humidity?
water dropping may be the culprit [shrug]
I know it happens because I've suffered from the effect [oddly it helped in one rifle and caused stuck bullets in another using the same casting run]

anyway.
my first powder coat run was with some bullets that had been sitting there for a few years, the next was from some I made a week before hand.

 

[Bret4207]

When I first started casting, I was flying solo for most of a year before finding that other site. The S&W 624 was leading, so I started reading current posts and rummaging round the dimly lit archive looking for answers. Some people said to use a soft/softer alloy, others said it use a hard/harder alloy, some said to air cool, still others said to water quench, and there were those who recommended an untold number of lubes. Through it all, there were some voices who weren't saying any of that. What they weren't saying was to use a soft/softer alloy, a hard/harder alloy, to air cool, to water quench, or try different lubes. In their own ways they were saying the path to success was to experiment.

As soon as the light became visible, I sold the hardness tester (ha, ha, let some other fool play that game!), and started making alloys till I found what my guns liked.

Ironically, or not, all those voices are this site's main characters and I continue to listen to and learn from them.

Listen to him Burbank

 

[462]

Listen to him Burbank

Bret,
You were one of the voices I listened to, back then, and am listening still.

 

[Bret4207]

Well, I got you fooled anyway.......

 

[462]

Well, I got you fooled anyway.......

Huh? Oh, wait, my hearing aid batteries died.

 

[popper]

I don't use tin, usually 2% Sb, PC and water drop after. About 4% Sb with some Cu (PC & WD) for toughness in HV (24-2700) 30cal. stuff. Did find 1% Zn & 1% Sb did well in 40sw & 30/30 light loads. Guess I just started hard and working my way softer till accuracy fails. I'm in the penetration vs expansion bunch. Some times I WD and some times AC depending on how lazy I am. I don't WD after HiTek (9mm & BO), coating got more brittle. It goes go on thinner and more consistent thickness than PC which should help for 223. I don't use it anymore, too much hassle. It does work.
For PbSn alloy, deformation starts about 9K psi applied in ~ a millisec. Additional tin increases psi a bit and temp decreases it a bit (~5%). For 50/50, 18K psi is deform point. SbSn alloy is a funny one, SnSb or Sn3Sb2, odd shaped structure. Pb2Sb with <0.5% Sb solubility. Sb2Cu5 & Cu2Sb with Cu solubility of 1.5%.
If you find a stress-strain curve approx your alloy, use the point where it just begins to flatten as the operating point.
edit: 1967 navel labs (millisec. hammer smash) test, pure Pb deformation is linear > 1k psi .

 

[burbank.jung]

Listen to him Burbank

I'm back. I hear you and like experimenting too. I've been flamed in other forums before for opinions based on findings from my experiments that worked. The opinions from seasoned casters is greatly appreciated. To relate to these casters, I use to ocean free dive and became fairly skilled at it but nothing to brag about. Among the group, most didn't say much unless the situation arose to educate someone. I have no interest in disrespecting anyone. I'm new to casting and most of my information is from books and the internet. When the opportunity arises I'll play/experiment with different alloys but for now, I'm starting with tests using the standard from books and expanding from there.

So, a new question. Does your accuracy load change according to lead hardness? Would it be the same as if you mixed different hard cast brands or the same powder from a different lot where the accuracy might be noticeable but significant. Do many of you run your PC bullets that expanded before loading?

 

[Bret4207]

I'm not flaming you guy, I'm trying to tell you that even though "hardness" seems like it should be a major component in successful cast shooting...it isn't! It's one small part among 25 or 30 or more parts. I'm trying to tell you that even though you will read all about lead alloys "melting" in the barrel and causing leading because the lead alloy is "too soft", and even though it seems intuitive that harder must = better, it isn't nearly that simple. Cast success comes from proper fit, and there are 2 parts to fit- static and dynamic. Bhn is a tiny part of dynamic fit. You will never, ever produce a cast bullet even beginning to approach the strength of a jacketed bullet. With all due respect, do what you want, but many of us spent years chasing the Bhn rabbit around the tree before we figured out a Bhn is basically meaningless. Just tryna save you some heartache. You want to read a book that gives you good info, the go to that Glenn Fryxell book I linked to earlier. You can forget 90% of what you read on the internet or see on You Tube as being worthwhile and helpful.

BTW- "HARDCAST" is a purely an advertising hype phrase. It has less meaning than "NEW! IMPROVED!" on toothpaste.

Does you accuracy change with Bhn? Yes, maybe and no. If it helps improve your fit, it can increase the good results. If it decreases your fit it gets worse. Or, it may have zero effect over several Bhn points. You want to experiment, then take air cooled castings and some water dropped castings and see if they differ with the same load in the same gun. My guess is you will see little if any real change if the load was decent to start with. Change seating depth, diameter, powder charge, sizing practices on case or bullet, lube, GC or bullet design and then you see real changes faster.

 

[Ian]

Short answer on BHN is yes, it alone can and does affect accuracy.

Long answer condensed is you have to really be pushing things hard in a very accurate gun before you will notice much difference.

So, respectfully, you may not be there yet. Spend your components working up acceptable loads and spend your time becoming a better shooter and enjoying the hobby. Cast your bullets from a wheelweight-ish alloy, don't over-do the tin, and learn how to adjust everything else to make that work. Once you master what it takes to get a basic ternary alloy to work, THEN tinker with metals and heat treating to see what it gets you.


The way to isolate bullet toughness as a factor is to heat treat and draw the bullets to a specific levels of hardness and shoot them while controlling all else to zero. Then you will see small differences in groups, if you shoot enough groups to be statistically meaningful.

 

[Rick]

Will the hardness effect your accuracy? Yes, maybe, very little. What will effect the accuracy is shooting bullets of different hardness within the same group. If you shoot a 10 shot group and the hardness of the bullets varies from say 12 to 18 you can pretty much expect shotgun patterns. Your accuracy can be acceptable shooting groups with 12 BHN or with 18 BHN but not mixed.

 

[Mitty38]

I am kinda new also.
But so far these fellows have not lead me wrong. Different path then the rest of the sheep travel but not the wrong one.

I have found out on my own that some times the wrong combination will just work, leaving you scratching you head.
Sometimes you can do everything by the book with procedures that "everyone" swears by. Still end up with scatter gun type groups.
Some times you just have to grab the bat, close your eyes and swing.

You can read, study, gather knowledge. But often the knowledge you gather will not click untill you put it into use.
There is a difference between knowledge and applied knowledge.

 

[popper]

For 50/50 PbSn alloy, deformation starts about 9K psi applied in ~ a millisec
1967 navel labs (millisec. hammer smash) test, pure Pb deformation is linear > 1k psi
This is what matters! BHN just measures deformation after a few seconds.
All the deformation occurs in LESS than a milisec. If pressure is too high, marshmellow down the tube. Less pressure, hot dog down the tube. It will fill the throat, then get sized by the bore. Fill the throat best you can by sizing, then rifling forces are all that deform. Jump or jam effects centering in the bore. So BHN is a nice reference to set YOUR alloy standard .
Edit: rifle barrel time for our cast is usually 1- 1 1/2 millisec total. Time to get into the bore is ~1/10th millisec. We can only guess what happens then. That is where malleability counts, not just BHN.
Using 180gr, H110 in GRT, I get 1" movement in 0.1 millisec and 5k psi. Fits to some pressure curves by Larry G, with a 'hickey' at the start, either primer ignition or hitting the bore. That gives ~ 3% deformation to pure, less to harder - but both must deform to fit bore. Kinda indicates soft should be greater than bore and harder closer to bore.

 

[fiver]

correct and then change where the bullet is during the sequence and things change again.

I kinda preach thinking about firing sequences as more where or when a bullet is, rather than part of the process at only 1-2 times during the sequence. [stopped or the end of the throat]
applying 50-K to only the base of a bullet fully supported by a .308 diameter steel tube is a lot different than applying 50-K to the base of a bullet still in a 310-311 funnel.

changing the BHN of a bullet or adding a slipper coating can change how it accepts those forces, because it can either change where the bullet is or how much the bullet is being forced to change shape.
either way I will guarantee those two bullets will not be in the same place when the same pressure is applied to them.

 

[Ian]

applying 50-K to only the base of a bullet fully supported by a .308 diameter steel tube is a lot different than applying 50-K to the base of a bullet still in a 310-311 funnel

Oh so much said right there alone.

 

[RBHarter]

And how many ways can an alloy be changed to achieve a BHN with a completely different bullet response ?

Let's dissolve some copper in ........

Cast bullets are like onions that keep growing while you're trying to peel them , they have layers and about the time you have them figured out you find some more .

 

[fiver]

yep, what's in there can get you to 2-K or 2600.
then you got the fact that some designs will do better with some alloy's, and some really don't care which one you use until you do go for the 2600 fps.

 

[Bret4207]

correct and then change where the bullet is during the sequence and things change again.

I kinda preach thinking about firing sequences as more where or when a bullet is, rather than part of the process at only 1-2 times during the sequence. [stopped or the end of the throat]
applying 50-K to only the base of a bullet fully supported by a .308 diameter steel tube is a lot different than applying 50-K to the base of a bullet still in a 310-311 funnel.

changing the BHN of a bullet or adding a slipper coating can change how it accepts those forces, because it can either change where the bullet is or how much the bullet is being forced to change shape.
either way I will guarantee those two bullets will not be in the same place when the same pressure is applied to them.

That right there should be a sticky of some sort. Well done!

 

[Bret4207]

And how many ways can an alloy be changed to achieve a BHN with a completely different bullet response ?

Let's dissolve some copper in ........

Cast bullets are like onions that keep growing while you're trying to peel them , they have layers and about the time you have them figured out you find some more .

Yup. You point out that most experienced casters can take 1 alloy and make it give 3 different readings or 3 different alloys and make them all read the same and it just goes right over their head. That frickin' Bhn and the term "hardcast" have done an incredible amount of damage to this hobby. Yeah, it as unintentional, but it's a huge hurdle to try and cross for most people.

 

[burbank.jung]

I am back. Thanks for your input. Since I last posted, I did the following. I took what ingots I had and separated them into three lots from soft, medium, and hardest based on the pencil scratch test. Then, I used the softest alloy to cast hundreds of .45 and .38 bullets for consistency. I have some left to cast 9-122 TC bullets. I plan to cast 9-122 bullets using some medium and hard alloy tested lots and compare test loads between them later. For now, I'll use the medium and hardest lead ingots to cast 9mm and .40cal bullets with the higher chamber pressures. More importantly, I'll have a consistent alloy for the brass/primer/powder combination for the best accuracy.

While I haven't done such a test, I am guessing that different alloy bullets shoot like different factory bullets like Speer and Winchester and Hornady of the same weight and same powder charge, case, primer.

I don't have much range time and have to ponder over your experienced advice. Using my knowledge to understand what all of you are saying, an undersized bullet at the worse is like a bullet being shot through a tube. As the diameter grows, it catches on the rifling and the rifling acts like a cheese grater. The burning powder and hot gases soften the lead and makes things worse. Eventually, bullet size is large enough so it obturates and deforms into the rifling. This holds the bullet in place so the bullet follows the channel (rifling) down the barrel. As pressure picks up, the bullet continues to deform to a point where there could possibly be leading (rifles?). This can be limited when gas checks are used because the copper base distributes the force like comparing kicking a cardboard box vs kicking a plywood plate that's been attached to the cardboard box. Even if the lead doesn't rub off in the barrel at this point, it deforms too much and accuracy suffers. If the lead alloy is harder, I need more powder to deform the bullet to fit the rifling.

Then there is PC. To me, PC is not a lube. It's more like a plated bullet except the plating is a shell of paint that encompasses the lead. During the painting process, the paint is melted into the lead molecule surface during the baking process. That's why when you hammer it, the paint doesn't come off. It's like leading a car to cover dents in Autobody, the lead molecules is soldered to the steel. My big problem here is that a thin coating of paint DOES rub off after I seat a bullet and remove it. Does that mean that there is exposed lead in my barrel? Well, the bullet is sized to my barrel so maybe the exposed lead bullet isn't noticed because of the fit.

So, my question here is am I on the right track? Brett, I want to experiment with your soft lead advice using the alloys I mentioned above and ( just remembering), some .22lr lead too to compare.

Thanks all

 

[Mitty38]

My big problem here is that a thin coating of paint DOES rub off after I seat a bullet and remove it. Does that mean that there is exposed lead in my barrel?

Me too.
I have always wondered about that, as I have had some "rub off" and some not, under different circumstances.
Yet in either instance, have found no leading, and very little plastic in my bores? Nothing a single pass with a nylon brush will not fix anyway.
Except one time, when I was hitting an extremely High BH(21) powder coated bullet, with a large amount of force. While playing with very fast powder.. lets just the primers were looking pretty iffy. And the retrived bullet was almost bare.