Hardness attained though different methods

[gnoahhh]

If this has been hashed out before, I apologize and respectfully request a link to the thread.

A question that has surfaced in my head from time to time is: does it matter how hardness is achieved, in terms of expansion in a target? What I mean is, does it matter whether a level of hardness is achieved through alloying, or heat treating, or what is used in the alloy, etc. to effect the end result? If a bullet has a bhn of 15, and the same bullet of a different alloy (or heat treated) with the same bhn of 15 is shot into test medium at identical velocities, will expansion be identical?

[Wayne Smith]

Yes and no. If the BHN is actually the same, then yes, there will be no difference. Realize, though, that achieving hardness through water dropping results in a slow change in hardness that may not ever be completely stable. For practical reasons you can assume that you will reach your full hardness in a couple of weeks and it will stay close to that for a long time.

The other issue you need to think about is boolit toughness. You might think of this as sheer resistance, how well the boolit holds together under the forces of impact. A hard, brittle boolit will come apart while a hard, tough boolit will hang together.

There have been a lot of posts on this issue of toughness over the years. Look for Felix's imput as this is valuable and reliable.

[prs]

I have not seen this discussed, but bet it has been. I am no metallurgist (nor speller), but I can give you my experiences. Yes, it matters. Some methods produce hard and brittle boolits and others produce hard and tough boolits. My take on it, is that alloys that are chilled to be hardened like good old time ww alloy also tend to be more brittle than an alloy that is naturally hard as air cooled like lino. Even if they test comparable RE hardness. The chilled pill tends to totally disintegrate on a steel plate (shatter?) while the hard unchilled pill loses its nose while the base and mid section falls to earth below the steel plate. I "think" tin helps toughen, but antimony in excess of what can properly combine with the tin tends to make brittle. But a good balance of tin to antimony (I kinda favor a ratio of 2:3 SN:SB) seems to make a tougher and harder pill (synergistic?). Now, there is no real science in my opinion, just rank obsevation; so the folks who really know can now set me and you both straight. Sometimes is good to muddy the water before clarification.

prs

[OuchHot!]

Hardmess and ductility are quite different concepts and both play into bullet deformation on impact.

[Larry Gibson]

There can be a lot of difference in the terminal affect of alloys with the same BHN. BHN only tells part of the story. Malleability is mostly the rest. Take HT'd or WQ'd WWs + 2% tin vs used AC'd linotype. Both can have a BHN of 18 - 22 depending on the percentage of antimony. The percentage of antimony in the linotype with be more than twice what it is in the WWs. Also the antimony will be higher than the soluability with tin in the ternary linotype alloy. Thus the AC'd linotype bullets with be brittle and shatter more easily that the much more malleable HT'dWWs + tin alloy which will expand. Same BHN, different alloy, one wil shatter and one will expand.

BTW; many time the more malleable alloy is also the more accurate one.

Larry Gibson

[Bret4207]

If this has been hashed out before, I apologize and respectfully request a link to the thread.

A question that has surfaced in my head from time to time is: does it matter how hardness is achieved, in terms of expansion in a target? What I mean is, does it matter whether a level of hardness is achieved through alloying, or heat treating, or what is used in the alloy, etc. to effect the end result? If a bullet has a bhn of 15, and the same bullet of a different alloy (or heat treated) with the same bhn of 15 is shot into test medium at identical velocities, will expansion be identical?

Yes, it matters. Different alloy makeup gives differing results and so does heat treatment. I've said before that I can produce the same Bhn from 3 different alloys. Anyone can, and on hitting the target the results will differ to a greater or lesser degree. A HT WW boolit at, say, 20 Bhn will give a different result than a high Sb HT boolit and a 20 Bhn Linotype boolit will give still a different result. Think of it in terms of cooking- With Bisquick, eggs and milk you can make biscuits, pancakes and dumplings, all with the same raw material. How you mix it and treat it gives you a differing result. Add way too much milk and you end up making crepes. Add too many eggs and you end up with...dog food? Deep fry it and you get a different result than if you steam it or bake it. Works about the same way with boolits, at least in my mind.

[runfiverun]

first question- yes
second question- no
how you achieve the final hardness matters in how the alloy reacts to impact and penetration.

[geargnasher]

Hardmess and ductility are quite different concepts and both play into bullet deformation on impact.

Exactly.

Brinell hardness is a measure of ultimate compressive strength of the alloy, an actual "hardness" test. Really, it means squat. Malleability is the key attribute.

Like Larry explained, you can make lead alloy hard by composition, or by heat treating. Linotype (12%Sb/4%Sn/84%Pb) has a BHN of 22 air cooled. I can heat treat a 3%Sb/2%Sn/95%Pb alloy to 22 BHN, they will dent the same under slow pressure. HOWEVER: Hit a linotype boolit with a hammer and it will shatter. Hit the heat-treated, softer alloy with a hammer and it will mash flat, it's the internal structure of the metal dentrites and how they react to impact that makes the most difference whe hunting, even though the two boolits have the same compressive strength.

The heat-treated, lower-antimony alloy will also generally shoot better because (I believe) it is able to flex and rebound better than a brittle boolit going down a barrel. Like a ping-pong ball vs one of those rubber bouncy-balls. They may have a similar compressive strength, but step on one and it crushes, the other will spring back to shape. Bore irregularities are hard on boolits, especially brittle ones.

Gear

[williamwaco]

Exactly.

Brinell hardness is a measure of ultimate compressive strength of the alloy, an actual "hardness" test. Really, it means squat. Malleability is the key attribute.

Like Larry explained, you can make lead alloy hard by composition, or by heat treating. Linotype (12%Sb/4%Sn/84%Pb) has a BHN of 22 air cooled. I can heat treat a 3%Sb/2%Sn/95%Pb alloy to 22 BHN, they will dent the same under slow pressure. HOWEVER: Hit a linotype boolit with a hammer and it will shatter. Hit the heat-treated, softer alloy with a hammer and it will mash flat, it's the internal structure of the metal dentrites and how they react to impact that makes the most difference whe hunting, even though the two boolits have the same compressive strength.

The heat-treated, lower-antimony alloy will also generally shoot better because (I believe) it is able to flex and rebound better than a brittle boolit going down a barrel. Like a ping-pong ball vs one of those rubber bouncy-balls. They may have a similar compressive strength, but step on one and it crushes, the other will spring back to shape. Bore irregularities are hard on boolits, especially brittle ones.

Gear


Two things:

First the "original" hardness test.

When I first started reloading we scrounged wheel weights. ( The more things change the more they stay the same.) After we cleaned them up and cast a few bullets we would take a bullet after it had cooled and lay it on a concrete floor or driveway and smack it with a hammer. If it flattened, we had a good alloy. If it shattered ( and many times they did ) we would add an equal amount of scrap lead to the mix.

Second regarding Linotype bullets. They are absolutely georgeous bullets. But in my experience they never shoot as well as the same bullet cast of wheel weights with a little tin added.

[gnoahhh]

Well, that sets it straight in my head. I've been casting for over 40 years and never paid much heed to hardness other than to monitor it with a hardness tester. I left the super hard bullets made of monotype and linotype behind long ago when I abandoned the chase for high velocity. Nowadays I'm happy in the WW+tin air cooled (11-13bhn) range for all of my shooting and life has been good accuracy and deer killing-wise.

My question stemmed from the fact that my stash of WW's is running low, but I have a huge stockpile of dead soft lead and a significant quantity of lino and monotype to sweeten it up to my preferred hardness range. My concern is not so much expecting the exact same accuracy. I can jockey things and re-experiment to get that back if need be, it's what the game is all about to me anyway. Rather, I was concerned about expansion on deer sized game in the 1800-2000fps range equaling what it is with my current alloy of WW+tin. The replies have given me the answers I sought, I think.

Which brings to mind a second question. Will my "new" alloy of lino + lead at bhn 11± age harden like my WW+tin alloy does? My SOP during deer season is to cast a handful a day or so before I'm hunting and load them up quick and repeat as necessary throughout the season so as to avoid letting the bullet I launch at a deer to have hardened to 14-15 or more (which is certainly within an acceptable range of hardness for expansion, but decidedly less so if velocity has fallen off to 1600 fps by the time the bullet hits the deer). I don't mind doing this, but it would be nice not to have to. Or am I worrying over nothing?

[btroj]

I am in agreement with Larry and Gear on this one. I want a bullet that will stay together on impact. I worry less about BHN and much more about alloy composition. I like to water drop everything out of habit so I use "softer" alloys that harden to give me the ability to shoot them at the speeds I want.

Getting hung pon BHN is a common trap for noobs. How you get the BHN is far more important.

[beagle]

I am of the opinion that casters of today strive for the hardness on cast bullets because that's what they have read that has worked for others over the years.

Now, I am also of the opinion that much time and effort and money is wasted by the average shooter in attaining a certain BHN that they feel is required to obtain good accuracy.

My old shooting partner was like that and worked at it dilligently. Most of his stuff was cast with #9 chilled (high antimony) shot alloyed with tin. He spent a lot of money and time to acheive accuracy and really was chasing his tail as my softer alloy bullets acheived and somtimes surpassed his accuracy. His bullets from a .32-40 and a .30/30 Winchester High Wall tended to break in half upon impact and he got way more leading than I did.

He water dropped and he heat treated as he had a heat treating oven as he was in the custom jewelry business and the results were about the same.

I acheived superb accuracy from only one batch of my bullets that were heat treated. Maybe that was a fluke but after a while, I gave up on the process and now only air cool.

For pistol rounds, IMO, it makes no difference and either heat treating, water dropping or air cooled work just as wel and a softer alloy allows for better bump in the trip from the case to the target.

For rifle bullets, I have had the best results with babbitt alloy air cooled bullets that weren't that hard but due to the copper from the babbitt alloy were tougher, but not necessarily harder and acheived better accuracy at higher velocities due to the "toughness".

IMO, it's not neccessary to chase the highest BHN that you can acheive but is better to find a softer bullet with a proper fit and the accuracy will be there with mimimal leading as a result./beagle