Cast bullet hardness and chamber pressure.

[mr.steve]

I'm trying to wrap my head around the various factors in casting and loading lead. I've heard the quick formula: "Take the hardness of an alloy, add two to the number, put two zeros on that, and you will have the approximate range you can shoot velocity wise." I average 875fps with 124gr PBRN over 5.1gr of #5, barrel is a Glock 26. The Bhn of the lead is 15.4 .

So, If I alloy my lead to a Bhn of 9.0 and use the formula my approximate usable velocity would be 1,100 fps. my reasoning here is I want the base of the bullet to obturate and fill the barrel completely. this will allow for accuracy and reduce leading. The information In the Hornady manual says to stay under 1,100 fps for lead. So far so good I think.

the instructions with the Lee hardness tester states the max psi for an alloy of 9.0 Bhn is 11,473 PSI. the reloading manuals show pressures of 30,000 to 34,000 PSI for loads comparable to mine. forgive me if I sound confused, it seems to be my usual state of mind lately. Sure, I'm over thinking this, I'm just trying to understand what I'm doing when I pour the bullets, reload , and unload them.

 

[wolfman]

I'm trying to wrap my head around the various factors in casting and loading lead. I've heard the quick formula: "Take the hardness of an alloy, add two to the number, put two zeros on that, and you will have the approximate range you can shoot velocity wise." I average 875fps with 124gr PBRN over 5.1gr of #5, barrel is a Glock 26. The Bhn of the lead is 15.4 .

So, If I alloy my lead to a Bhn of 9.0 and use the formula my approximate usable velocity would be 1,100 fps. my reasoning here is I want the base of the bullet to obturate and fill the barrel completely. this will allow for accuracy and reduce leading. The information In the Hornady manual says to stay under 1,100 fps for lead. So far so good I think.

the instructions with the Lee hardness tester states the max psi for an alloy of 9.0 Bhn is 11,473 PSI. the reloading manuals show pressures of 30,000 to 34,000 PSI for loads comparable to mine. forgive me if I sound confused, it seems to be my usual state of mind lately. Sure, I'm over thinking this, I'm just trying to understand what I'm doing when I pour the bullets, reload , and unload them.

First of all, a soft alloy can cause "severe" problems in a Glock due to lead shear as the bullet has no sharp edges to grip it to start it turning as it goes down the barrel. There is a lot of good information out there about the risks of shooting lead in a Glock, and IMO, if you are going to do it in a factory barrel, you should be up in the 20Bnh+ range. Otherwise get a good aftermarket barrel such as Wolf to shoot lead through.

Second, my target Bhn for my .45, .40, and .357 is 15.5, so I would recomend using what you have with no alloying.

 

[mr.steve]

Thanks wolfman, I forgot to mention I have a Lone Wolf barrel for the Glock when I shoot lead. I figured why take a chance. I've heard that wheel weights are a softer alloy so I could just melt, flux and pour without any additional tin or antimony. Roto Metals is my only reliable source right now.

 

[wolfman]

I get my wheel weights from a tire shop, and they are a mix of clip and stick on. I don't sort them before smelting, usually end up around 15 to 16 Bnh, and if I need a harder bullet for my .480, water drop to get a hardness of 20+.

 

[sbcman]

I'm trying to wrap my head around the various factors in casting and loading lead. I've heard the quick formula: "Take the hardness of an alloy, add two to the number, put two zeros on that, and you will have the approximate range you can shoot velocity wise." I average 875fps with 124gr PBRN over 5.1gr of #5, barrel is a Glock 26. The Bhn of the lead is 15.4 .

So, If I alloy my lead to a Bhn of 9.0 and use the formula my approximate usable velocity would be 1,100 fps. my reasoning here is I want the base of the bullet to obturate and fill the barrel completely. this will allow for accuracy and reduce leading. The information In the Hornady manual says to stay under 1,100 fps for lead. So far so good I think.

the instructions with the Lee hardness tester states the max psi for an alloy of 9.0 Bhn is 11,473 PSI. the reloading manuals show pressures of 30,000 to 34,000 PSI for loads comparable to mine. forgive me if I sound confused, it seems to be my usual state of mind lately. Sure, I'm over thinking this, I'm just trying to understand what I'm doing when I pour the bullets, reload , and unload them.

First off, you're going to be fine with your casting and reloading. Along the process you might find small tweaks in your lead and load that can improve accuracy/reduce leading, etc. It's a process of discovery. For example, I've pushed a 124gr lead bullet well over 1100 with no leading or accuracy problems.

The difference your seeing between Lee's advice and your loading manuals is simply this: Lee is telling you the the psi needed for the bullet to obdurate. He has a fixation with this concept and dedicates a huge portion of his reloading manual to it. The published loads data don't care about bullet obduration. They are interested in velocity at various distances and therefore shape their loads accordingly.

 

[mac45]

Just so happens there's a similar thread over at Castboolits right now.
Richard Lee's "system" of matching cartridge pressure to metal pressure.

 

[sbcman]

Not to thread jack, but I've read that part of Lee's manual probably 10 times and I'm still not certain about everything. It seems to me that in handgun calibers this isn't as critical an issue. I can see it being much more valuable in rifle bullets, but I don't cast or reload rifle rounds so I've never experimented with it. The biggest issue I've found with Lee's conclusions is that different lead can have the same bhn but still be different (think lino, for example). Just seems hard to make it a one size fits all proposition. I've personally found bullet size to make more a difference in leading and small tweaks in the load to make more of a difference in accurracy

Still, Lee has forgotten more about casting than I'll ever know, so I highly respect his advice.

 

[kludge]

Here's another opinion...

Missouri Bullet Company

 

[mr.steve]

You haven't hi jacked the thread, this is still good information. The way I look at the hobby is since I have so much control over the components I should strive to have the most accurate, cleanest and cost effective ammunition. 'sides, the more I load the more I shoot.

 

[mr.steve]

That's a good read, thanks kludge. that article talks about the same issues I'm concerned with, mainly accuracy and the effects of leading on accuracy.

After shooting lead (200-300 rounds) I have inspected the barrel while cleaning. I'm not sure if I have leading in the barrel or not.

 

[wolfman]

That's a good read, thanks kludge. that article talks about the same issues I'm concerned with, mainly accuracy and the effects of leading on accuracy.

After shooting lead (200-300 rounds) I have inspected the barrel while cleaning. I'm not sure if I have leading in the barrel or not.

Here is a good test to see if you have leading. Run a " Very Loose fitting" patch soaked with either Krol or transmission fluid through the bore to get it really good and wet, then set it aside for a couple of hours. Once the lube has had time to leach under any lead in the barrel, take a piece of flannel material fold it at least once to bulk it up so it fits very tight in the bore, and push it through once. Any leading should show up as little metal slivers stuck to the flannel, and if there are none, you have found yourself a load combo that works in your gun.

 

[kludge]

It'll make a mess of the brush, but if you wrap a patch around a brush, you will see flakes of lead on the patch... if you don't see flakes, you don't have a leading problem. If you have a leading problem you'll see it a lot sooner than 200-300 rounds!

edit: wolfman beat me to it!

 

[mr.steve]

all right! I have noticed that. Tiny silvery flakes on a tight patch. It's not been much. I had been viewing through the barrel pointed at a bright light source. it sure looked clean to me that way.

 

[Sirshredalot]

Hmm...I tend to shoot harder bullets(18bhn) at around 800-850fps.

I havent had much "leading"...in the way of metal slivers or flakes, but i do get a BOATLOAD of bullet lube "fouling"...anyone else get this?

God bless
-Shred

 

[mr.steve]

now I'm thinking I should work toward a better fitting bullet. I've lapped my molds and it has helped some I think. When I slugged the three barrels I shoot lead with I found the 9mm LW barrel is 0.3562, Colt 1911 is 0.4542 and the Rossi CJ is 0.4560. my 9mm mold is a Lee DC 356-125-2R. The .45 mold is a Lee DC 452-230TC. Lapping added a little over 0.0015 to the bullet diameter. I tumble lube and size to 0.357, 0.454, and 0.457. needless to say but the sizing just kisses the sides part way around on all but the 0.457.

 

[XtremeVel]

Here's another opinion...

Missouri Bullet Company

I don't cast my own, but between ordering from & taking the advice of MCB, and on occassion ordering from Dardas, I have always been more than happy with the results.

 

[wolfman]

All of my molds are Lee Tumble Lube design, and I don't size, just shoot as cast with good results. I cast for .45's, 40's, 357's, a .357sig, tumble lube with a 50/50 mix of Alox and Johnsons Paste Wax, and have no leading. Because the bands on the Lee TL design bullets are so thin, sizing isn't recomended, since the edges will easily fold back as much as necessary, and form a very good seal.

 

[mr.steve]

wolfman, your bullets have more than one groove for lube. I was lucky to get the molds I have. Mine have only a single groove hence a wider lip . I also use the 50/50 LLA/JPW. Hopefully, when the "investors" stop buying everything in sight I'll get some TL molds. I still have back orders pending from FS Reloading.

 

[Leo]

Even this old guy has learned something in the last couple years, thanks to some of the ingo friends that shoot a lot of lead. I had given up on straight lead and shot copper plated NBC bullets for 20 plus years until they went out of business and then switched to Rainier. For low velocity bullseye loads, I have to agree, that soft alloy bullets are actually cleaner with less leading. I started buying the 12 brinel hardness bullets and found that I can take them up to full .38spl and .45acp velocity and still get good results. I also shoot 18 brinel bullets at regular loads and I really do not loose any accuracy, but I get more lead build up in the rifling, especially in the first couple inches of the barrel. I still prefer plated or jacketed bullets in the 9mm and .40 S&W or magnums.

I had previously tried going the other way. I even tried baking the bullets for an hour at 300 degrees and dumping them in water to "surface harden them". I saw it in an old reloaders manual. I think it actually made the bullets worse, plus I had to lube them after that waste of time.