hardness vs brittleness

[nanuk]

on many occasions I have read posts that make comments about hardness/toughness/brittleness

I would like to put it into one thread so I can save it for later reference.

so, I ask the experts this specifically:

Heattreated WW vs harder alloy.

If WW is HT to the same BHN as Lino, it is as hard.

but it will not be brittle?



the comments that come to mind are that for hunting, we want a tough, malleable boolit. Lyman#2 is reported to be a bit brittle, Whereas HTWW is hard but will not fragment easily and make a good hunter.


so, If I need a hard boolit due to my specific rifle caliber/cartridge/velocity goal, HTWW is a better option if available than going to a harder alloy such as Lino?

hope I made some sense.....

[btroj]

You have it right. Straight Lino will be a hard but brittle bullet. On impact with bone it may fracture rather than expand and hold together.
I personally would prefer 50/50 ww/lead heat treated for hunting. I might even go 60 % lead for hunting. I want a bullet that is tough, which to me means it will expand, it will bend, but it worn break.
This is not really different than steel. I want a knife that is hard enough to hold a good edge but if not annealed it will also be brittle and will break easily. I also once was shooting a couple gongs a guy made my FIL. One was plain steel plate, the other a piece of the edge from a snow plow blade. Plain plate crated, was punctured by high velocity stuff, bent, etc but stayed in one piece. The plow blade never dented no matter what we hit it with. The plow blade did, however, after 50 or so impact break cleanly. The plow blade was hard, but it was also brittle. I could not punch a hole thru it but I could break it.

I hope this gives you some idea of what you need. You have a good grasp of the basic ideas.

[lwknight]

I can tell you that the #2 is not any kind of brittle. It is more ductile and tougher than the hardball 2-6-92.
Tin makes alloy strong and tough. Antimony makes alloy hard and even brittle.
Tin offsets the brittleness with toughness.

Pure lead bullets can and will tear apart or erode and adding a little tin will make them hold together and still mushroom completely.

[felix]

Manganese is to steel as antimony is to lead. ... felix

[lwknight]

I believe that heat treating bullets is 1. A way to get extremely hard bullets. 2. The poor mans hardener because they lack antimony.
Tin and antimony are expensive. Your best hunting alloy will cost more than a make-do hardening method.

[Larry Gibson]

nanuk

Yes there is a definate difference in "hardness".. many use the BHN as a measure but it does not tell the difference between brittle and malleable alloys. Suggest you pick up a copy of Lyman's #3 Cast Bullet Handbook and read;

The Metallurgy of molten Lead Alloys, by Dennis Marshall

Cast Bullets for Hunting, by C. E. Harris and Dennis Marshall

Many of your questions will be answered there.

For hunting big the bullet, if expansion is wanted, should be hard enough to withstand accelleration and malleable enough to expand without shattering. If expansion is not wanted it should be hard enough to not readily expand yet not brittle so that it shatters.

For HV the bullet also needs to be hard enough to withstand accelleration and yet not brittle so that the rifling does not chip the driving bands. This generally is a most satisfactory type alloy for HV varmint loads in smaller callibers whose bullets have small width driving bands.

Some alloys serve a wide band of performance levels and other alloys only a narrow band of performance.

Larry Gibson

[Doc Highwall]

I cannot add much to what has already been said except a little on metal being ductile. The most ductile metal in the world is gold and you can take a very small piece and place it between two pieces of leather and keep hitting it and it will just keep getting thinner and more spread out with out splitting or work hardening. That is how they make gold leaf. You can hammer on tin and it will flatten out but at some point it will split, do the same thing with antimony and it will shatter like glass. This is why the black powder shooters use only lead/tin alloys like 20:1 or 30:1 or some other ratio of lead/tin because they are ductile.

[onondaga]

Heat treating is not permanent and in 1-2 years the treated bullets will return to about as cast BHN.

#2 alloy stays #2 alloy hardness, it is not a brittle alloy and the first recommended alloy for a universal hunting bullet for lots of good reasons.

The old guides manuals recommend #2 and describe your rifles maximum humane kill range as that distance where there is remaining 1000 foot pounds of energy to expand #2 alloy bullets to double in diameter upon striking game animals. That is what #2 does and does well as a standard for hunting.

Here is an example determining maximum humane kill range with a ballistic chart:

http://i30.photobucket.com/albums/c338/rhymeswithwhat/458Bal.jpg

This #2 alloy bullet, at my muzzle velocity specified, will humanely kill North American game animals at 200 yards.

Here is an example with a different caliber #2 alloy bullet, can you pick the maximum humane kill range?

http://i30.photobucket.com/albums/c338/rhymeswithwhat/X39Bal.jpg








Gary

[nanuk]

thanks Guys, I knew I could count on this forum for some great responses.

this thread will be put into my archive with a few others.

Just one question, Doc Highwall... Can you send me some of Your GOLD alloy boolits??? I'd like to try some testing... I won't need much, perhaps 5000 .501cal 750grainers for my muzzleloader? I will pay shipping!

[Lloyd Smale]

the only bullets ive seen fracture at handgun velocitys have been bullets cast out of water dropped ww. Now im no expert on metals and im sure ill get arguments but ive shot LOTs of linotype bullets and have yet to see one fracture in a penetration test or on game. I saw 4 water dropped ww bullets fracture in the same day out of 3 different guns at a linebaugh semianar one year and have seen others in my own testing do the same. Mostly swcs and the nose sheared off.

[Larry Gibson]

Lloyd

Got to consider the target. Linotype usually isn't a favored alloy, among others, for silhouette shooting as the bullets shatter on the steel and don't many times don't maintain the momentum to knock the steel over, especially the rams. A more ductle alloy is often favored.

Larry Gibson

[Lloyd Smale]

Larry ive yet to see a bullet that didnt shatter on steal. I havent shot much silhouette but have shot many plate shoots and have heard the same mumbled by guys there. Even after i take there trophys home using hard bullets. I would have to think with silhouette shooters using handguns at the ranges they do that the bullets are traveling slow enough by the time they get out there that an differnce they are seeing is more in there heads then reality. Maybe 44 mag will chime in as hes done alot of it.

[waksupi]

Well, my quenched .358 boolits don't shatter on steel. Friend was somewhat perturbed that I was making holes in his 5/8" targets at 200 yards.

[clodhopper]

Around 1981 -1985 with the then current wheel weights I was casting lee 130 grain 7MM bullets. Then loading them in a 14" barreled contender 7mm TCU at around 1900 FPS.
Many of those bullets fragmented into tiny peices on impact.
Perfect for ground squirrels, skunks and rabid cats.

[Larry Gibson]

Lloyd

Many do but some don't. In the case of silhouettes it is a case of how fast they "shatter". You might not think there isn't a difference but there actually is. When a bullet shatters it ceases imparting momentum to the steel target. The longer it holds together the more momentum imparted to the steel target and the steel gets knocked over. A linotype bullet with a BHN of 22 will shatter quicker than a bullet made of WQ'd alloy with the same 22 BHN. One may not knock the steel target over when one will with the same hit.

It's easy enough to measure. Many years ago before the availability of easily used chronographs a ballistic pendelum was used to determine the major/minor factor of reloads in numerous IPSC competitions. Major power scoring factor was set by how far the pendulum swung after the steel face was impacted by using .45 ACP hardball factory ammuntion. Your reloads had to swing the pendelum the same amount or farther. A simple device it was but was not in use long with the advent of easily used chronographs. The point is with numerous cast bullets from 190 - 230 gr it was quickly found that linotype alloy made it difficult to achieve major with any reasonable load. The same bullets cast of WWs with the same load at a slightly less velocity easily moved the pendelum and made major. I had a chronograph then (Oehler M11) and also chronographed some of the various loads. Interestingly the 230 gr cast bullets always had to be higher velocity to achieve major than with jacketed hardball. The very hard cast bullets, usually cast of linotype, had to be really pushed to a much higher velocity to make major if they did at all. This was with numerous cartridges not just the .45 ACP.

It all had to do with how long the bullets stayed together after impacting the steel. It's the same on steel silhouettes. Back when handgun silhouette shooting "took off" there were numerous articles in the AR and monthly gun magazines concerning this subject.

Larry Gibson

[felix]

Years ago, Larry, I called that phenomenon "stick time". I wrote to friends (by letter) about how to select bullets, make boolits, which work on whatever targets like plates, trees, bricks, etc. That was back in the mid 70's when the sillywet games were going full time. However, I never could tell a hunter about anything because I had zero experience, and still don't. ... felix

[Larry Gibson]

felix

I now recall the term "stick time", thanks for jogging the memory.

Larry Gibson

[cbrick]

Heat treating is not permanent and in 1-2 years the treated bullets will return to about as cast BHN. Gary

From all of my testing and from several others testing this old wives tale this is simply not true. HT Pb/Sb (lead/antimony) alloys will age soften but far slower and to a much less extent than is commonly believed and endlessly repeated keeping the old wives tale alive and well.

I did a BHN test on HT'd 30 BHN bullets stored at room temp for 10 years and they were 26 bhn. That's hardly the 12 BHN they were before heat treating 10 years earlier.

If you have an unusualy high Sn (tin) percentage in relation to the antimony percent your age softening will be somewhat faster. If you have an unusualy high Sn (tin) percentage in relation to the antimony percent the initial amount of strengthening (hardness) will also be somewhat less.

Rick

[Doc Highwall]

"stick time" I always called it Dwell Time and learned that bullets with a greater sectional density at a lower velocity were better at knocking the rams down then a lighter bullet at higher velocity.

[cbrick]

Stick time is good, I also called it dwell time. The amount of time from the instant the nose contacts steel until the rear of the bullet finds the target, imparting it's full energy (momentum) onto the target. This is where high antimony bullets fail on steel targets, the rear never gets to the target, it comes apart when the nose hits the target and doesn't impart full momentum to the target and leaves the highly prized and sought after steel sheep standing there . . . laughing at you.

Rick

[Larry Gibson]

Funny how sometimes an old essoteric subject shows up at the same time. On another forum here there is a thread regarding a ballistic pendelum used to calculate velocity. A poster there mentions the use also back in IPSC shooting of using the ballistic pendelum to determine major/minor power for scoring.

"Dwell time" also works for me and also applies to time inside a target as in a game animal or 2 legged varmint.

Larry Gibson

[BABore]

Since TOT (Time on/over Target) is already taken, how about TIT (Time in Target)?:groner:

[nanuk]

or Time At Target...

then when argued, it could as simple as TIT for TAT?

:groner: :groner: