BHN standard for cast bullets ?

[Scibaer]

i have read that the BHN for lead, is 5.0 ( pure lead ) to values of over 22.0
i see that alot of bullet casters , that sell cast bullets for reloading offer bullets for hunting in the range of BHN 15 or 16.
 now that is the standard deviation of hardness of aluminum ..
now the question.. why is the standard BHN hardness for cast bullets about 15 ? same as a slug of aluminum ?
is that by chance or design ?

[Nobade]

Most commercial cast bullets are 15 BHN because commercial casting alloy makes bullets that hard. This is a compromise, they are too hard for low pressure rounds like 38 spl. They are too soft for very high pressure rounds, say 357 mag at its upper limits. Ideally bullets should be tailored to their intended use, softer for low pressure and harder for higher pressure. But commercial casters aren't going to provide that, it is what you do with your own bullets when you make them yourself for best performance.

As for aluminum, the hardest bullet casting alloys are no where near as hard as the softest aluminum. I think you may have your hardness scales confused.

[Scibaer]

ok, its most likely i do. i reload and i got a good grip on it, but im now getting into the bullets, casting and whatnot.
and im reading and that leads to questions and simple experiments.
i guess what im looking for, is some real world base line that i can measure and see, what a BHN of 15 or any number is..
another question is, how far in hardness is say a BHN of 15 from  16 or 18.. is it progressive or scaled ? or ...

[mdi]

Don't know about BHN having a linear scale, but I have used wheel weight alloy (9-12 BHN) for many years without problems. When I'm mixing for general bullet casting I shoot for 10-12 BHN as this has been working for me in all my handguns. In my case, bullet fit outweighs BHN by a long shot, meaning fit is more important than BHN. If the bullet fits my gun properly I can shoot soft (8-9 BHN) to light magnum speeds, 1100+ fps, with no leading.  I have shot .357 Mag. 150 gr. SWC cast from wheel weights, air cooled, over a slightly over max. load of True Blue and had no leading because I sized the bullet to fit my gun (best guess was near 1400 fps). If a bullet is too small, no matter what the BHN, it will lead the cylinder throat, cylinder face, forcing cone and barrel. If it's too big chambering problems occur.
Commercial casters also use harder alloys  because they hold up better during shipping; fewer dings/dents. Same with lube; a harder lube stayes in the groove during shipping...

[Hairy Chest]

If you want better than jacketed performance with cast, then why go soft?  Harder bullets maintain form stability.  Even low pressured rounds do great with jacketed and jacketed is hard.  Shooting putty plugs creates all kinds of problems.   

[Richard P]

For ''home cast'' bullets, you can make them as hard or as soft as you require.  Pure lead is usually 5 on the BHN scale.  Older years' clip on WW (air cooled) usually ran 12 or 13.  Water quenching it may harden it just a small amount.  To get into harder bullets you need to alloy with linotype or if you want (and can find) straight lino----it is reputed to go 22 BHN.
Some alloys used hard birdshot as it contained arsenic in trace amounts and contributed to hardness in heat treated and then water quenched bullets.  Lino has a unique alloy of lead, tin, and antimony. About 2% tin will aid in castability and raise hardness (lead and tin) to probably BHN 8.   Most consider more than 2% tin as excessive and costly.  Antimony contributes most to hardness especially in HT / Q bullets. 
   I believe it was Dennis Marshall who wrote a very respected article in the American Rifleman some years back entitled ''Stronger bullets with less Alloying''  or a title to that effect.  He discussed the traits of alloys, their point of solidification and uses. 
You'll have to decide what hardness value you need.  Then research how to get it. 

[Hairy Chest]

For ''home cast'' bullets, you can make them as hard or as soft as you require.  Pure lead is usually 5 on the BHN scale.  Older years' clip on WW (air cooled) usually ran 12 or 13.  Water quenching it may harden it just a small amount.  To get into harder bullets you need to alloy with linotype or if you want (and can find) straight lino----it is reputed to go 22 BHN.
Some alloys used hard birdshot as it contained arsenic in trace amounts and contributed to hardness in heat treated and then water quenched bullets.  Lino has a unique alloy of lead, tin, and antimony. About 2% tin will aid in castability and raise hardness (lead and tin) to probably BHN 8.   Most consider more than 2% tin as excessive and costly.  Antimony contributes most to hardness especially in HT / Q bullets. 
   I believe it was Dennis Marshall who wrote a very respected article in the American Rifleman some years back entitled ''Stronger bullets with less Alloying''  or a title to that effect.  He discussed the traits of alloys, their point of solidification and uses. 
You'll have to decide what hardness value you need.  Then research how to get it.

Good information.  Just to correct you.  If you have WW's that air cool 12-13, water dropping will make them BH 21 or higher.  If you add Sb to that, you'll be BH30 in no time. 

[jhalcott]

 I see a very important question not being asked! WHAT do you want YOUR bullets to do? Targets with handguns do not require hard bullets and high velocity. Hunting requires a some what harder alloy. I use straight air cooled wheel weight alloy for deer hunting a softer aloy for 44/45 caliber pistols Linotype for SOME rifle targets and in my .44sbh. BUT THAT'S MY IDEA! I have used straight acww alloy for all of the above uses at times. I suppose since the old WW's +2%tin were about 15 BHN that became a standard. Fit is much more important than BHN. I've read of guys shooting pure lead that fit the guns correctly at quite high velocity with no undo leading!

[BCB]

 I hear the high BHN numbers for wheel weights as being 12-13 and some claim 15…
 
I have old WW that are nearly 20 years old as well as new ones, and I can’t get a BHN of 10.  That is testing them with a SAECO hardness tester.  I think they are good…
 
Even the SAECO hardness comparison chart that converts the SAECO numbers to BHN only list WW at a BHN of 9…
 
Lyman #2 runs at BHN of 15 as I have some of that and my SAECO tester verifies that.  I doubt that any WW would ever reach that hardness level.  Water cooling may get them near that, but I am uncertain that 15 can be reached…
 
Heat treating only works with WW if you add some antimony.  I used hardened shot to get some of my 280642 and 287346 near the BHN of 22-25.  But that can be a bit tricky, depending on the shot added.  Good hard shot can be difficult to find anymore…
 
As far as shooting the 357 Magnum and “magnum” pressures, I use pure WW at the BHN of 8-9 and I have no problems at all.  Very minimal leading at the muzzle of a Security-Six is about it.  Just fired 50 rounds in it today and a dry patch through the barrel showed nice shiny rifling—only a bit of a “wash” at the muzzle.  These are 358429’s that are a Keith-style boolit and have no gascheck…
 
I think BHN is thrown around without doing the actual testing using good lead testing devices…
 
Just my thoughts…
 
Good-luck…BCB
 

[Hairy Chest]

I've read of guys shooting pure lead that fit the guns correctly at quite high velocity with no undo leading!

That's pretty amazing when you think about it.  How good can a putty plug do when it is being deformed.  Maybe at short range - 50 yards is max for WC's that are almost pure.  Better is jacketed out to 100 yards with spot on accuracy.  How does it do it?  It is hard, so it doesn't deform.  It maintains it's shape.  Harder alloy also grips the rifling better.  Also, harder reduces base obturation, resulting in lower pressures. 

[Hairy Chest]

I hear the high BHN numbers for wheel weights as being 12-13 and some claim 15…
 
I have old WW that are nearly 20 years old as well as new ones, and I can’t get a BHN of 10.  That is testing them with a SAECO hardness tester.  I think they are good…
 
Even the SAECO hardness comparison chart that converts the SAECO numbers to BHN only list WW at a BHN of 9…
 
Lyman #2 runs at BHN of 15 as I have some of that and my SAECO tester verifies that.  I doubt that any WW would ever reach that hardness level.  Water cooling may get them near that, but I am uncertain that 15 can be reached…
 
Heat treating only works with WW if you add some antimony.  I used hardened shot to get some of my 280642 and 287346 near the BHN of 22-25.  But that can be a bit tricky, depending on the shot added.  Good hard shot can be difficult to find anymore…
 
As far as shooting the 357 Magnum and “magnum” pressures, I use pure WW at the BHN of 8-9 and I have no problems at all.  Very minimal leading at the muzzle of a Security-Six is about it.  Just fired 50 rounds in it today and a dry patch through the barrel showed nice shiny rifling—only a bit of a “wash” at the muzzle.  These are 358429’s that are a Keith-style boolit and have no gascheck…
 
I think BHN is thrown around without doing the actual testing using good lead testing devices…
 
Just my thoughts…
 
Good-luck…BCB

That's funny.  I have some WW's here that hardened dandily and no Sb was added.  I do know that the arsenic in WW's does allow for hardening.  As you say though, it is good to have some mag shot handy if they aren't getting hard enough. 

[Bigeasy]

I've read of guys shooting pure lead that fit the guns correctly at quite high velocity with no undo leading!

That's pretty amazing when you think about it.  How good can a putty plug do when it is being deformed.  Maybe at short range - 50 yards is max for WC's that are almost pure.  Better is jacketed out to 100 yards with spot on accuracy.  How does it do it?  It is hard, so it doesn't deform.  It maintains it's shape.  Harder alloy also grips the rifling better.  Also, harder reduces base obturation, resulting in lower pressures.

 
 
Casting hard lead bullets is not the cure all to leading.  In a revolver with matching cylinder throat / bore  sizes, and assuming decent rifling, and bullet lube, a hard cast bullet will work fine.  Problem is when a shooter gets a lot of leading, his natural instinct is to cast harder; but that is often a mistake.
 
When a hard cast bullet is fired in a revolver with improperly sized throats or bore, gas cutting around the base of the bullet will occur, causing leading.  This is why gas checks often result in a reduction of leading.  In such a weapon, the use of a softer bullet will allow it to "slug up" to fit, decreasing leading, and often improving accuracy.  Colt SA revolvers in .45 Colt are a good example of this, with their mis-matched cylinder throat / bore diameters.  A softer bullet is usually the cure to leading and accuracy problems.
 
For best accuracy and leading reduction, both the cylinder throats and bore should be measured.  If they are in sync. - say .357 throats and bore, for a 38spl. / 357 mag, then you should be good to go with a hard cast bullet sized .001 / .002 over.  If the throats are under bore diameter by .001 or more, an easy fix is to have them opened up.  Its when the throats are quite a bit larger then bore diameter that you really tend to run into leading, with no easy mechanical cure.  That's where soft cast, or jacketed can make a real difference.
 
As velocity increases to the point softer cast bullets begin to strip on the rifling, or bases are distorted by heavy powder charges, then gas checks, harder bullet, or jacked are warranted.  The reason jacketed bullets usually do so well in most guns is because being jacketed, there is no leading issue, and jacket material is quite a bit harder then lead, allowing the bullet to grip the rifling without stripping, even if the bullet / bore match is not optimal.  Pushed at normal handgun velocities, soft cast bullets do not become shapeless blobs of lead.  At most, they stay round, and slug up to match the diameter of the bore.  A properly sized and lubed cast bullet can be just as accurate as a jacketed bullet - just look at the groups the guys who shoot in the various long range vintage rifle matches are getting with their open sighted 45/70's, using relatively soft, cast slugs.
 
Larry

[BCB]

That's funny.  I have some WW's here that hardened dandily and no Sb was added.  I do know that the arsenic in WW's does allow for hardening.  As you say though, it is good to have some mag shot handy if they aren't getting hard enough.

"Heat treating only works with WW if you add some antimony".

I will admit that that statement is somewhat incorrect.  WW do contain antimony as well as small amounts of arsenic.  But how much does the hardness increase without the addition of some more of the two mentioned?

What hardness tester are you using to verify the increase in hardness?

BCB

[Hairy Chest]

I've read of guys shooting pure lead that fit the guns correctly at quite high velocity with no undo leading!

That's pretty amazing when you think about it.  How good can a putty plug do when it is being deformed.  Maybe at short range - 50 yards is max for WC's that are almost pure.  Better is jacketed out to 100 yards with spot on accuracy.  How does it do it?  It is hard, so it doesn't deform.  It maintains it's shape.  Harder alloy also grips the rifling better.  Also, harder reduces base obturation, resulting in lower pressures.

 
 
Casting hard lead bullets is not the cure all to leading.  In a revolver with matching cylinder throat / bore  sizes, and assuming decent rifling, and bullet lube, a hard cast bullet will work fine.  Problem is when a shooter gets a lot of leading, his natural instinct is to cast harder; but that is often a mistake.
 
When a hard cast bullet is fired in a revolver with improperly sized throats or bore, gas cutting around the base of the bullet will occur, causing leading.  This is why gas checks often result in a reduction of leading.  In such a weapon, the use of a softer bullet will allow it to "slug up" to fit, decreasing leading, and often improving accuracy.  Colt SA revolvers in .45 Colt are a good example of this, with their mis-matched cylinder throat / bore diameters.  A softer bullet is usually the cure to leading and accuracy problems.
 
For best accuracy and leading reduction, both the cylinder throats and bore should be measured.  If they are in sync. - say .357 throats and bore, for a 38spl. / 357 mag, then you should be good to go with a hard cast bullet sized .001 / .002 over.  If the throats are under bore diameter by .001 or more, an easy fix is to have them opened up.  Its when the throats are quite a bit larger then bore diameter that you really tend to run into leading, with no easy mechanical cure.  That's where soft cast, or jacketed can make a real difference.
 
As velocity increases to the point softer cast bullets begin to strip on the rifling, or bases are distorted by heavy powder charges, then gas checks, harder bullet, or jacked are warranted.  The reason jacketed bullets usually do so well in most guns is because being jacketed, there is no leading issue, and jacket material is quite a bit harder then lead, allowing the bullet to grip the rifling without stripping, even if the bullet / bore match is not optimal.  Pushed at normal handgun velocities, soft cast bullets do not become shapeless blobs of lead.  At most, they stay round, and slug up to match the diameter of the bore.  A properly sized and lubed cast bullet can be just as accurate as a jacketed bullet - just look at the groups the guys who shoot in the various long range vintage rifle matches are getting with their open sighted 45/70's, using relatively soft, cast slugs.
 
Larry

As a minimum, the bullet has to be sized correctly with lead.  Perhaps you can get away with some obturation with soft and undersized, but why bother?  Make it the right size to begin with.  I like my clothes fit the body, not wide, baggy pants or a shirt 2 sizes over on me.  Plus, I'm not going 2,600 fps or spinning one hundred thousand revolutions.   

Jacketed can be undersized.  You can shoot a .308 jacketed bullet in a .311 bore in 7.62X 39 caliber, but not with a cast or you will have problems.  Again, that is because a jacket is hard,  the way we want our lead to be on the outside. 

[Hairy Chest]

That's funny.  I have some WW's here that hardened dandily and no Sb was added.  I do know that the arsenic in WW's does allow for hardening.  As you say though, it is good to have some mag shot handy if they aren't getting hard enough.

"Heat treating only works with WW if you add some antimony".

I will admit that that statement is somewhat incorrect.  WW do contain antimony as well as small amounts of arsenic.  But how much does the hardness increase without the addition of some more of the two mentioned?

What hardness tester are you using to verify the increase in hardness?

BCB

I use the Lee tester.  It works well.  Those are the results of my WW composition.  I am not a metallurgist and have no way of knowing exactly what is in these biscuits.  I just know how to take what I have and get it to where I need for optimal performance. 

[mdi]

Those "putty bullets" (?) prolly shot without leading because they obiturated to fill the cylinder throat and the groove diameter. Leading isn't lead "rubbing off" on the barrel, but most often by hot gasses leaking around the bullet base and melting lead and depositing it on the barrel...

[jhalcott]

 Get veral Smith's book, Jacketed performance with cast bullets. This is a reference book that will answer your questions. Veral can make you a mold too.

[Hairy Chest]

Most commercial cast bullets are 15 BHN because commercial casting alloy makes bullets that hard. This is a compromise, they are too hard for low pressure rounds like 38 spl. They are too soft for very high pressure rounds, say 357 mag at its upper limits. Ideally bullets should be tailored to their intended use, softer for low pressure and harder for higher pressure. But commercial casters aren't going to provide that, it is what you do with your own bullets when you make them yourself for best performance.

As for aluminum, the hardest bullet casting alloys are no where near as hard as the softest aluminum. I think you may have your hardness scales confused.

This is a fallacy.  If you make the bullet the right size, you can shoot BH 33 and will get the best groups ever with a .38 Special.  That is how you shoot small groups at 100 yards.  You need a bullet that can fly.  Can you throw a football?  Mess it up to change it's configuration and see how far it flies.  Soft lead does that.  Why do they use jacketed for 1000 yard matches?  Because you need a hard bullet to maintain the aerodynamics.  Veral calls this in his book 'form stability'. 

Likewise, a harder bullet grips the rifling better with stout loads.  You need a stout load to shoot at long range. 

Better to have a long range load that shoots at short range than a short range load that can't shoot long range. 

[anachronism]

However, if you are hunting with these bullets. or even shooting steel targets, the overly hard bullets tend to shatter when they hit a hard target. This reduces, or even eliminates penetration in game, or results in silhouette targets failing to fall over because of incomplete energy transfer. Lymans #2 alloy is about bhn 18, and wheelweights commonly run around bhn 14 (for me, there are lots of variables).  Overly hard plain base bullets can also allow flame cutting at the base if everything isn't balanced out in your load. I've cast bullets from monotype for 45 acp that, fractured at the taper crimp line. It was kind of neat in a way, but they were horribly inconsistent because the ose of the bullet would come off in the feeding cycle. These bullets tested out at bhn 28 IIRC.

Verals book is a real treasure. I suggest everybody interested in cast bullets buys it, and reads it several times. It's the best $20.00 a bullet caster could ever spend.

[Hairy Chest]

However, if you are hunting with these bullets. or even shooting steel targets, the overly hard bullets tend to shatter when they hit a hard target. This reduces, or even eliminates penetration in game, or results in silhouette targets failing to fall over because of incomplete energy transfer. Lymans #2 alloy is about bhn 18, and wheelweights commonly run around bhn 14 (for me, there are lots of variables).  Overly hard plain base bullets can also allow flame cutting at the base if everything isn't balanced out in your load. I've cast bullets from monotype for 45 acp that, fractured at the taper crimp line. It was kind of neat in a way, but they were horribly inconsistent because the ose of the bullet would come off in the feeding cycle. These bullets tested out at bhn 28 IIRC.

Verals book is a real treasure. I suggest everybody interested in cast bullets buys it, and reads it several times. It's the best $20.00 a bullet caster could ever spend.

The fracturing isn't due to hardness, but alloy content.  You need to re-read the section titled 'Performance Testing.' 

[Lloyd Smale]

Im one that likes a harder bullet. Even at low velocitys if the gun is a good one and the bullet is sized properly a hard bullet will usually outshot a softer one. As to the fracturing hitting steel about any bullet hitting steel will fracture if theres any kind of velocity behind it. Even jacketed soft points do it. Ive heard all the storys about harder bullets not knocking down steel but have used linotype bullets in steal plate shoots and for shooting silhoette comp and never saw it myself. If a target didnt fall it was my fault for a poor hit not the bullets. As to bullets fracturing ill say this. Ive been to a few linebaugh seminars where we did extensive penetration testing. I once took 3 place in the tests with a 340 grain lfn out of a lowly 44 mag cast out of lineotype. What effects penetration more then anything is a bullet deforming. if a nose rivets or deforms in any way penetration and the ability of a bullet to tract straight inside of an animal suffers alot. Only bullets i saw in all my penetration testing at home and there that actually fractured were comercial bullets that were water dropped. high antimony content alloys like ww water dropped make for a brittle bullet. Ive yet to see a lineotype bullet fracture in a penetration test of any kind out of a handgun.  back to accuracy. I chuckle at guys that preach the soft to bump up therory. How do you expect a bullet to be accurate if it deforms before it even leaves the barrel? If  a gun is so bad that it improves by doing this you need to fix then gun as all your doing is putting bandaid on a compound fracture! Id bet that 99 percent of those that believe in softer bullets to bump up have never shot a one inch 50 yard group with a sixgun.

[Hairy Chest]

Im one that likes a harder bullet. Even at low velocitys if the gun is a good one and the bullet is sized properly a hard bullet will usually outshot a softer one. As to the fracturing hitting steel about any bullet hitting steel will fracture if theres any kind of velocity behind it. Even jacketed soft points do it. Ive heard all the storys about harder bullets not knocking down steel but have used linotype bullets in steal plate shoots and for shooting silhoette comp and never saw it myself. If a target didnt fall it was my fault for a poor hit not the bullets. As to bullets fracturing ill say this. Ive been to a few linebaugh seminars where we did extensive penetration testing. I once took 3 place in the tests with a 340 grain lfn out of a lowly 44 mag cast out of lineotype. What effects penetration more then anything is a bullet deforming. if a nose rivets or deforms in any way penetration and the ability of a bullet to tract straight inside of an animal suffers alot. Only bullets i saw in all my penetration testing at home and there that actually fractured were comercial bullets that were water dropped. high antimony content alloys like ww water dropped make for a brittle bullet. Ive yet to see a lineotype bullet fracture in a penetration test of any kind out of a handgun.  back to accuracy. I chuckle at guys that preach the soft to bump up therory. How do you expect a bullet to be accurate if it deforms before it even leaves the barrel? If  a gun is so bad that it improves by doing this you need to fix then gun as all your doing is putting bandaid on a compound fracture! Id bet that 99 percent of those that believe in softer bullets to bump up have never shot a one inch 50 yard group with a sixgun.

Maybe 50 yards, but what does that prove?  Soft as putty WC's do that.      Then we have those guys who shoot BCPR.  How doe their soft bullet win meets?  I don't know, Lloyd.  Maybe it is the low pressure they are using.  Maybe it is the low pressure of .38 Spl that allows some deviation from the norm. 

[gypsyman]

HairyChest, alot depends on the firearm being a revolver, or single shot. Bullet jump in a revolver can really screw up a bullet if the cylinder isn't aligning with the barrel. On the other hand, a single shot rifle of pistol, with a short jump from the chamber into the barrel, and a throat thats been tapered for cast bullets, can be amazingly accurate, with dead soft bullets. Getting the bullet to obturate and seal off the burning gas's is the main thing. Buffalo hunters and all the wars fought with guns before jacketed bullets, had some amazing shots. One that sticks in my head, is a story about a buffalo hunter down in Texas back in the 1870's or 80's. The fort wasn't much as I remember reading, and they were surrounded by Indians. After being pinned in for several days, and not getting any help, a buffalo hunter took aim at the chief, who was mounted on a horse about a mile away. Took him out, and all the rest left.I can't remember for certain, but it was either a 45/70 or 45/90. And I'm quite certain, back then, they weren't hunting down wheel weights, hardened shot with arsnic, or heat treating the bullets. I'm pretty sure that they were shooting pure lead, or something close to it.If you do some research, I believe that their still holding a shooting match to this day trying that very shot. Not sure where. gypsyman

[Lloyd Smale]

you cant compare what it takes to make a black powder centerfire rifle work to what makes a smokeless powder revolver work. Two totaly differnt senerios there. Ive shot alot of cast bullets in my days. Shooting one inch groups at 50 yards with any wadcutter is pretty rare. My posts come from my experience in the field not from someone elses theroys or internet garbage. For an expample a few years back my buddy and I and hes probably one of the most experienced loaders and shooters in the country, tested a pile of ammo. We had two model 25 smith 45acps. two 45 1911s, two 38 special smith 15s and two smith 29s. We loaded 5 differnt bullet designs in each and used 3 different powders with each. We then proceded to shoot those bullets cast out of 5050 ww/pure, straight ww, 5050 ww/linotype and staight linotype to see if there was any alloy that would consistantly be better. We found in every case but one that the harder the bullet the better the accuracy we got. Only exception was one bullet with one powder in one 25 smith that did  best with straight ww. Most groups with the 5050 ww/pure were double what the groups were with harder alloys. Sure this isnt a wrote in stone scientific study but it showed just what we had noticed over the years in all of our guns. If a gun has proper dimentions and a good barrel it will about allways shoot a harder alloy better then a softer one. Im not trying to say you cant make softer alloys work. Ive done it myself but I can about guarantee you that the average guy who doesnt want to spend 6 months at the range tweeking loads will do himself a big favor by starting out with a bullet (in a revolver) that is at least 12 bhn. Im also not saying that the old timers (some which i respect very much) were wrong when they preached soft bullets bumping up to bores. Back then the guns they dealt with had cylinders and bores that matched about as well as putting a pinto motor in a f15. the only way they could get any semblence of accuracy was using bullets about as hard as bubble gun and hoping theyd at least enguage the rifleing after being swadged down through a tight forcing cone. Bottom line is if your gun needs soft bullets to shoot well you need to work on your gun.

[Hairy Chest]

It looks like the original poster was trying to say soft is better, but that premise was rejected.  It turned in the other direction, to a harder bullet!   

[Scibaer]

im the OP. no i was not saying that any particular hardness was better.
i was asking if a bhn of of 15 or 16 was the optimum beacuse thats what i seem to find that casters online offer.
 i was trying to find out what the best all around bhn was for a hunting handgun.
but as  the thread took off, alot of it went over my head.
 i do get that a hard bullet will deform less and function better

[Lloyd Smale]

to answer your question yes 15-18 bhn is about optimum for a hunting bullet. its hard enough to be accurate and bust bone without deforming at handgun velocitys. ive shot quite a few deer, pigs, bear and buffalo with handguns and most times when i head to the field to hunt the alloy i use is 5050 ww/lino air cooled and it runs right in that range.

im the OP. no i was not saying that any particular hardness was better.
i was asking if a bhn of of 15 or 16 was the optimum beacuse thats what i seem to find that casters online offer.
 i was trying to find out what the best all around bhn was for a hunting handgun.
but as  the thread took off, alot of it went over my head.
 i do get that a hard bullet will deform less and function better

[anachronism]

However, if you are hunting with these bullets. or even shooting steel targets, the overly hard bullets tend to shatter when they hit a hard target. This reduces, or even eliminates penetration in game, or results in silhouette targets failing to fall over because of incomplete energy transfer. Lymans #2 alloy is about bhn 18, and wheelweights commonly run around bhn 14 (for me, there are lots of variables).  Overly hard plain base bullets can also allow flame cutting at the base if everything isn't balanced out in your load. I've cast bullets from monotype for 45 acp that, fractured at the taper crimp line. It was kind of neat in a way, but they were horribly inconsistent because the ose of the bullet would come off in the feeding cycle. These bullets tested out at bhn 28 IIRC.

Verals book is a real treasure. I suggest everybody interested in cast bullets buys it, and reads it several times. It's the best $20.00 a bullet caster could ever spend.

The fracturing isn't due to hardness, but alloy content.  You need to re-read the section titled 'Performance Testing.' 

This is only partially true. For example, I recently remelted a batch of H&G 503s that I had cast and water dropped to harden. 48 Hours after casting I hammer tested sample bullets, and the samples fractured. After remelting & recasting, I air cooled the bullets instead. 48 hours later, the samples did not fracture when hammer tested. The rate that a lead & antimony based alloy cools affects it's hardness (of course), and also caused larger dendritic crystals to form in the bullet. The larger the crystals, the more fragile the bullet. Lyman refers to the dendritic crystals as "grain structure" in their cast bullet manuals. Veral also addresses this particular issue in his book. This situation meshes with Lloyds observation of heat-treated lino bullets breaking apart on steel targets (see above post). Lloyds suggestion of 50/50 lino/WW is spot on for hunting, and most other purposes.