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Slinger
06-04-2012, 02:49 PM
Two questions for the experts! How long should you let your alloy set/cure before taking a hardness reading? I've got an LBT Tester. If I'm looking for a BHN of 9, and it comes up 10 or 11, is that enough difference to re-melt and add some lead? I'm going to use it in a .44 Special for milder handloads say no faster than about 750 fps.

RobS
06-04-2012, 03:05 PM
If antimony is present in the alloy it takes a week or so and if arsenic is in the alloy too (wheel weight alloy) then around 3 or 4 days for all practical purposes as it relates to loading and shooting them. This is what I've noted anyway take it for what it's worth.

wiljen
06-04-2012, 03:17 PM
This is some work I did on that subject a few years ago that you might find interesting.

http://www.castpics.net/subsite2/GeneralReference/The%20Myth%20of%20Arsenic.pdf

Slinger
06-04-2012, 04:46 PM
Thanks fellas! I thought it was about 72 hours. And, the article was interesting as well.

Second question though- Is there all that much difference between a bullet with a BHN of 9 vs. 11? Or stated another way, for obturation using mild loads is 11 BHN too hard in the .44 Special? I've never done much with mild target loads, so I don't know what to expect.

geargnasher
06-04-2012, 05:01 PM
We have some debate here about the term "obturation", so it's tough to know exactly what you mean. If you're asking if the boolit is soft enough to "bump" under pressure and expand to seal (obturate) the cylinder throat and ultimately the bore, that depends on how much pressure you put to it and how fast (charge weight and powder burn rate). Ideally, no such bumping takes place, so the boolit can't deform in ways you don't want it to that affect accuracy in a bad way.

All that being said, just let them sit a couple of weeks to age-harden fully, load them, and shoot them. If they're the right size and you don't punch them too hard, you'll be fine.

Gear

Dan Cash
06-04-2012, 05:15 PM
Second question though- Is there all that much difference between a bullet with a BHN of 9 vs. 11? Or stated another way, for obturation using mild loads is 11 BHN too hard in the .44 Special? I've never done much with mild target loads, so I don't know what to expect.

I shoot a similar spread of hardness in a .44 Special and .45 Colt. The special gets a 250 grain bullet with 6 to 6.5 gr Unique and the Colt gets 8 grains of the same under a 250 grain bullet. Cast them, lube them and shoot them and don't worry about hardness or aging. If they fit they won't lead.

Slinger
06-04-2012, 06:04 PM
I shoot a similar spread of hardness in a .44 Special and .45 Colt. The special gets a 250 grain bullet with 6 to 6.5 gr Unique and the Colt gets 8 grains of the same under a 250 grain bullet. Cast them, lube them and shoot them and don't worry about hardness or aging. If they fit they won't lead.

That's what I'm using in the .44 Sp., 6.0 of Unique and 5.0 Unique using the DEEP SEAT Method that J. Taffin wrote about. I was using slugs cast out of 7 BHN and they shot just fine...no leading. I sized them to .430" to the .429" bore as the throats are .433" I had no luck- accuracy-wise with the slugs @ .432" so I decided to go the other way. When I sized to .430" the accuracy improved quite a bit. I'll get the results I'm after, it's just a matter of tinkering around.

Slinger
06-04-2012, 06:17 PM
We have some debate here about the term "obturation", so it's tough to know exactly what you mean. If you're asking if the boolit is soft enough to "bump" under pressure and expand to seal (obturate) the cylinder throat and ultimately the bore, that depends on how much pressure you put to it and how fast (charge weight and powder burn rate). Ideally, no such bumping takes place, so the boolit can't deform in ways you don't want it to that affect accuracy in a bad way.

All that being said, just let them sit a couple of weeks to age-harden fully, load them, and shoot them. If they're the right size and you don't punch them too hard, you'll be fine.

Gear
I really don't know that obturating/bumping to fill/seal the throats is always key to accuracy. My throats are .433", bore is .429". I sized to .430" and get decent accuracy. I can't see where swaging the bullet down .003"when it hits the bore will enhance accuracy or deter leading. That hasn't been my experience with this particular revolver. Now I have a Ruger Blackhawk ,45 Colt with approx. .001" between the throats and bore and the gun is extremely accurate. So no doubt there is a correlation there, but I'll go with sizing to the bore the bore when the throats are way off........Just my opinion/experience. I do appreciate your views though!

lwknight
06-04-2012, 06:41 PM
One of the common problems you run into with revolvers is cylinder throats squeezing the bullets down. You should be able to shove a properly sized bullet through the cylinder throat with your bare thumb even if its tight , its OK.
If you can't then you need to investigate the throat size.

Slinger
06-04-2012, 07:04 PM
I've never run into the throats being smaller than the bore. That would be an easy fix with a properly sized reamer. My throats are oversize in this particular gun.

melloairman
06-04-2012, 09:50 PM
Two questions for the experts! How long should you let your alloy set/cure before taking a hardness reading? I've got an LBT Tester. If I'm looking for a BHN of 9, and it comes up 10 or 11, is that enough difference to re-melt and add some lead? I'm going to use it in a .44 Special for milder handloads say no faster than about 750 fps.
I keep a close tab on my range lead and scrap lead that I melt into ingots .And some of it will take up to 20- 30 days to cure to its hardest bhn . Some will hit 12 bhn in 7-10 days and set there for another 7 days and begin to harden more . I have learned to just let it set for 30 days and check it then .Marvin

Slinger
06-05-2012, 08:50 AM
I keep a close tab on my range lead and scrap lead that I melt into ingots .And some of it will take up to 20- 30 days to cure to its hardest bhn . Some will hit 12 bhn in 7-10 days and set there for another 7 days and begin to harden more . I have learned to just let it set for 30 days and check it then .Marvin

Geez! I'm too old to wait that long!!!!!!!! Time's a wastin'. 3-4 days will have to do as it's not that critical to me.

melloairman
06-05-2012, 10:12 AM
Consistency = accuracy .Marvin

Slinger
06-05-2012, 11:35 AM
Consistency = accuracy .Marvin

Yeah, it's hard to argue that simple statement .........................so, I guess I'll have to give up some accuracy as time is of the essence.

RobS
06-06-2012, 01:30 AM
Geez! I'm too old to wait that long!!!!!!!! Time's a wastin'. 3-4 days will have to do as it's not that critical to me.


Yeah, it's hard to argue that simple statement .........................so, I guess I'll have to give up some accuracy as time is of the essence.

You don't have to give up accuracy due to time constraints, there is another way. If you have an old toaster oven lying around, or any oven for that matter, you can speed up the age hardening of antimony based alloys. I simply use a convection toaster oven because the wife would skin my hide if I used her kitchen oven. Can’t blame her really, I’m also not a fan of using kitchen items in tandem with my casting equipment.

Anyway, once the boolits have cooled from casting simply put a batch of them in an oven at 190-200 degrees F for an hour and leave them in there to cool. WW alloyed bullets will reach their hardness in 48 hours or so. Another option for a quicker turn-around is to do two exposures in the oven with 7 to 8 hours between each session reducing the time to less than 24 hours. Remember my experiences are with WW alloy which as arsenic in them and helps speed up the aging process. A straight lead to antimony alloy would likely take longer.

Due to time limitations during certain parts of the year I do this so I can cast one day and then shoot the next, again using WW boolits. This works with air cooled or even water quenched.

gray wolf
06-07-2012, 06:44 PM
Anyway, once the boolits have cooled from casting simply put a batch of them in an oven at 190-200 degrees F for an hour and leave them in there to cool. WW alloyed bullets will reach their hardness in 48 hours or so. Another option for a quicker turn-around is to do two exposures in the oven with 7 to 8 hours between each session reducing the time to less than 24 hours. Remember my experiences are with WW alloy which as arsenic in them and helps speed up the aging process. A straight lead to antimony alloy would likely take longer.

This seems to contradict what I have read, NOT saying it's wrong.
I thought you placed the bullets in a toaster oven ( or similar )
at 450* for an hour and then quenched them in cold water.
Wouldn't heating and slow cooling anneal ( soften ) the lead bullets.
Could someone clear this up for me as I would like to harden some bullets that were cast a while ago.

thank you

lwknight
06-07-2012, 07:14 PM
You are correct that slow cooling would prevent potential hardening.
Quite simply , the structure would have large crystals of antimony and hard alloys have a very fine grain structure.

RobS
06-07-2012, 11:33 PM
At 200 degrees it only speeds the aging process, I am not annealing the boolits. I've been doing this for a long time and have run side by side comparison between those that were treated at 200 degrees in the oven and those that were allowed to age on their own. In the end both sets of bullets will reach the same hardness. Its been pointed out that a person can't bring an antimony based (WW) bullet's water quenched bhn hardness down by putting them in boiling water (212 degree F at sea level). It simply takes more heat to anneal the bullet.