BPCR alloy

[MaLar]

OK I have a question for you guys and gals. I used to shoot BPCRS a long time ago.
I'm going to get started again in the spring. Jezzz how things have changed.
I was shocked at the price of tin when I went shopping. I used to buy solder 95/5 for $9 a pound.
It's hard to find around here for under $35 now. I can buy it online for $10+ a pound plus shipping.

OK now the question, I have about 650 lbs of lead and 1200 lbs of lino and mono I bought years ago for .25 a pound. Can I make a usable alloy from this? If so what mix? I do have some tin but not much.
I know you can use pewter for tin but around here they think it's gold.

[country gent]

I use a 20-1 lead tin alloy for my grease grooved and paper patched bullets that is working real well for me. Some are goping to a small amount of antimony also now. I havent tried it yet. My bullets are probably around 10 bhn. Ive never tested for hardness but did try diffrent alloies and let my rifles tell me what they wanted. Early on I tried some Laser cast 500grn hard cast and got disapointing accuracy with the hard 18-20 bhn bullets. I believe they werent bumping up to seal the bore with Black Powder. The softer alloys work better for me and my rifles. You might try 20 lbs pure lead with 1 lb lino and go from there. I dont smelt and blend my own alloy anymore I just order the desired alloy and run with it.

[Gunlaker]

20:1 and 16:1 are very popular alloys.

Some are using alloys with a small amount of antimony in them. If you do some digging through past posts you'll find the information that you need.

Chris.

[Chill Wills]

You need to consider the bullet design - maybe. For the older blunt nosed bullets almost any alloy in the 9 -12 BHN range will work.
For the longer nosed Money type a stronger alloy will keep the unsupported nose from slumping out of balance.

[Chill Wills]

A good sample alloy (using what you have) for the Money bullets cast in a 20 lb trial pot is the following mix.

3 lbs Lino
15 lbs plain lead
to this add only 1 oz tin

the additional tin will bring the tin total in the pot to about 1%. This is important - do not use more.

This ratio is quick and dirty and will make an alloy of about
97 Pb
2 Sb
1 Sn

It will have a hardness of about 12-13 and be time stable. This will support any BPCR Nose.

You can get out the calculator and scale but this will be close enough.

[BrentD]

Last time I checked John Walters was selling tin for $15/lb. I have enough to probably last the duration of the BPCR game, or next year, whichever comes first :(

Anyway, you might check with him if you want to do a straight lead-tin alloy, which, as Chill Will says, generally runs 16 or 20:1, I prefer the former. Compared to all the other stuff that goes into the game, I don't find the tin price to be too terribly onerous.

Chill Will is probably the master at making wheel weights and antimony lead work. You couldn't be in better hands there. :)

[MaLar]

Firstly Thanks for your replies. I guess I could have give a little more info.
I'm shooting a roller in 40-65, Douglas 34" 16" twist barrel. Boolits are a copy of the Lyman Postell and the Lyman pointy one 410660.
I also used the RCBS 40-300 SP CSA 300 grn mold on chickens.
I was using 20-1 when I was last shooting this game.

[rfd]

Firstly Thanks for your replies. I guess I could have give a little more info.
I'm shooting a roller in 40-65, Douglas 34" 16" twist barrel. Boolits are a copy of the Lyman Postell and the Lyman pointy one 410660.
I also used the RCBS 40-300 SP CSA 300 grn mold on chickens.
I was using 20-1 when I was last shooting this game.

1:20 sounds good, greasers? if so, maybe 1:30 is worth testing.

[Gunlaker]

I shoot two different bullet designs out of a Shiloh 1:16 twist .40-65. A non-pointy Saeco #740 which works well with 20:1, and a pointy "money" bullet which is more consistently accurate with 16:1. I have yet to try Chill Will's alloy for the money bullet but I have no doubt that it would work very well.

Chris.

[Lead pot]

When you add antimony to your mix you can cut down on the tin.
Example, 1/16 tin/lead say for a PP money bullet type ogive is pretty much normal what most use and it holds the nose setback to around .027" using black powder in a .45-90 from what I have measured and it will fill the grooves for good rotation.
19 pounds of pure lead and one roll of 95/5 no lead solder that is 95% tin 5% antimony will hold the nose setback the same as 1/16 T/L with the same load. Just that small amount of antimony makes this much difference.
1/19 tin/lead the nose setback will be around .067" average and that is enough for the nose to get setback enough that the lands will engrave on the bare lead ahead of the patch.
1/25 T/L with the money nose it will look like a postell when shot with black powder.
Here is a very good link to get alloy composition information from that very few use. http://www.lasc.us/Fryxell_Book_Chapter_3_alloySelectionMetallurgy.ht m

[John Boy]

Words from Dan Theodore ...
My favorite antimonial alloy is the 97.0 / 1.5 / 1.5, which has a BH of 9.8 and took 18 hours to completely age-harden. It has remained at that hardness for over one year

lead/tin/antimony all by weight
97.0 / 1.5 / 1.5 : 7 parts lead + 3 parts Lyman # 2

Q: How do you make #2 Alloy?
A: To make 10 pounds of #2 Alloy, use either of the following recipes: 9 pounds of wheelweights + 1 pound of 50/50 (lead/tin) bar solder or 4 pounds of Linotype +1 pound of 50/50 bar solder + 5 pounds pure lead

[Lead pot]

Mr. Pope also wrote about that mix also quite often. It is almost like the old Lyman #1 alloy.

[John Boy]

And what is currently forgotten, is in history Dr Hudson shot many famous groups using 1:14 using the 319293 and 375292 Ideal bullets - breech seated

[Chill Wills]

Q: How do you make #2 Alloy?
A: To make 10 pounds of #2 Alloy, use either of the following recipes: 9 pounds of wheelweights + 1 pound of 50/50 (lead/tin) bar solder or 4 pounds of Linotype +1 pound of 50/50 bar solder + 5 pounds pure lead

I'm not sure anyone can turn 3% Sb into 5% Sb by diluting it.
I think this notion comes from an almost century old (almost[smilie=1:) Lyman text. Wheel weights may have been different then.

:-D :mrgreen::drinks:

[Tom Myers]

For those that need to view the calculations, the images below are from the Precision Cast Bullet Alloy Calculator (http://www.tmtpages.com/Alloy/alloycalc.htm).

The first three images display the number of ounces of each individual alloy component to make 18 pounds of Dan Theodore's recommended 97 - 1.5 - 1.5 alloy.

The purpose of Lyman #2 can loosely be interpreted as containing equal amounts of Tin and Antimony in the alloy.

Wheel weights and 50-50 solder won't quite make the cut to achieve the 90 - 5 - 5 ration of Lyman # 2. The closest we can come with equal weights of Tin and Antimony is adding 19 ounces of Tin to 269 ounces of wheel weights to obtain a 92.5 - 3.74 -3.74 alloy.

Adding pure tin to the wheel weights is not quite as good. Although the Antimony level in the wheel weights is not high enough to bring the ratio up to equal the Lyman #2. About the best that can be done with wheel weights and Tin is to add 10 ounces of tin to 278 ounces of old wheel weights to achieve 18 pounds of a 92.27 - 3.86 - 3.86 alloy.

The last image displays the ratios to make 18 pounds of Lyman #2 Alloy from Linotype, Tin and Lead.
Add 10 ounces of Tin and 147 ounces of pure Lead to 131 ounces of Linotype. Resulting in the true 90 - 5 - 5 alloy.

Hope this helps.

BPCR alloy from Lyman #2

http://www.tmtpages.com/LinkSkyImages/forum_images/Alloys/Alloy-BPCR-with-Lyman%232.PNG


BPCR alloy With New Wheelweights

http://www.tmtpages.com/LinkSkyImages/forum_images/Alloys/Alloy-BPCR-with-new-wheelweights.PNG

BPCR Alloy With Old Wheelweights

http://www.tmtpages.com/LinkSkyImages/forum_images/Alloys/Alloy-BPCR-with-wheelweights.PNG

Lyman # 2 with Wheel-weights and 50-50 Bar Solder

http://www.tmtpages.com/LinkSkyImages/forum_images/Alloys/Alloy-Lyman%232-with-wheelweights-and-50-50-solder.PNG


Lyman # 2 from Wheelweights and Tin.

http://www.tmtpages.com/LinkSkyImages/forum_images/Alloys/Alloy-Lyman%232-with-wheelweights-and-Tin.PNG

True Lyman #2 with Linotype, Lead and Tin

http://www.tmtpages.com/LinkSkyImages/forum_images/Alloys/Alloy-Lyman%232-with-Linotype-Lead-and-Tin.PNG

[BrentD]

Tom,
Tha'ts a pretty handy calculator you have there. I made one for just lead-tin alloy, but nothing half as involved as this. Good info!

[Tom Myers]

Tom,
Tha'ts a pretty handy calculator you have there. I made one for just lead-tin alloy, but nothing half as involved as this. Good info!

Thanks Brent.

It does get rid of the guesswork and also eliminated the math mistakes that I was continually making. Best of all though, the panels can be printed out so's I don't forget when I go to the casting room

[SgtDog0311]

From BrentD “Chill Will is probably the master at making wheel weights and antimony lead work. You couldn't be in better hands there. ”

Good to know Brent! I try to always put authoritative gauge on who I’m reading before I store the info. Can’t remember where but somewhere I stored in my brain that it is important to have equal amounts of tin and antimony. But I admit the alloy business has always given my pea-brain fits. This and the Money Bullet thread over on BPCR has been good for me to read but I still have questions based on that nugget I stored away some time back.

My background: I have shot smokeless for the last several years. I only started casting in 2010 but I’m retired and dive in pretty deep so casting for about 13 rifles. But this year shot my first BPCR and so now my interests have changed (not leaving my vintage levers behind but Single Shots and BPCR has got nearly all my attention now).

The problem is that I have way more wheel weights than money - so looking for a way to get about 600lbs of WW, taken from a 1960 vintage crane where it served as ballast, into the mix. I’m shooting a variety of bullets so far, but mostly trying to feed two 40-65s, a 38-50 and a 35-40 for Black Powder loading. The molds I have are a Paul Jones with a fairly blunt ogive for the 40-65 (would like to add the BACO M409400 and maybe the Saeco 740) , a Steve Brooks for my 38-50RH and another Steve Brooks I had modified from the Sage Chicken Money Bullet to fit my rifle’s dimensions. Here is a picture of nose profiles I currently have; you already know the profiles for the BACO and the Saeco.

40-65 and 38-50RH
182716

35-40
182717

So the question: Since WW start out with too high of antimony to get to DanT’s optimal antimony alloy of 97.0 / 1.5 / 1.5, and since I have that 'nugget' of equalizing tin and antimony in my head, I’m wondering if I added 2% tin to the WW I have, would that come close to Tom’s calculations and even-out the tin and antimony, and would that be fit for GG bullets sized .001 over groove? I’m afraid I know part of the answer since these WWs are from the 1960s and reputedly have higher antimony than today’s WWs. But thought I'd ask.

Obviously I’m looking for a way to avoid the expense of buying pure lead or even 16:1 or 20:1. Buying linotype would not be any better on the pocketbook.

[BrentD]

John, I can't help ya. Chill Will and Leadpot can though, of that I'm pretty sure. I just stay away from wheel weights because the get too complicated for my little mind to figure out and manage. But those guys make'em work.

I am, however, happy to see you fully addicted to BPCRs. Addictions like that make me feel warm and fuzzy all over. There is still hope for this world yet.

Good luck,
Brent

[Lead pot]

John.

Beltfedarnie on the Shiloh forum would be a good guy to ask about WW GG bullets also. He uses that alloy and does quite well with it at the 1K matches. Ask Arnie what he uses for his GG .40. My use for the WW alloys are just for curiosity what the alloy does for ogive setback and deformation when the charge goes off and how the different ww alloys allow the PP bullets to fully expand filling the grooves. I have a bunch of WW ingots that go way back into the late 60's but they are for future use incase I cant get lead.

Kurt

[BrentD]

This is a slight deviation from the intent of this thread, and I apologize for that, but maybe it would be helpful. For those that have been shooting both .45s and .40s with high precision, does the .40 bullet need to be as hard as the .45 with a given nose shape, and still produce top-drawer accuracy? I would think that maybe .40s could be a bit softer and not slump by virtue of being lighter in absolute terms.

[Lead pot]

This is a slight deviation from the intent of this thread, and I apologize for that, but maybe it would be helpful. For those that have been shooting both .45s and .40s with high precision, does the .40 bullet need to be as hard as the .45 with a given nose shape, and still produce top-drawer accuracy? I would think that maybe .40s could be a bit softer and not slump by virtue of being lighter in absolute terms.

If you have some to see what is going on with your bullets send me some marked with numbers on the base for your references and I will give them a test with my .40-70 or .40-65 and give me the load info of the load you will be using and I will send them back when I recover them. The rifles don't have the fast twist like yours has. I'm running some tests now for the .45-90 and .50-90 for next season using Swiss loads........Kurt

[BrentD]

Kurt, if it warms up enough to cast, count on it! I would love to do that. We don't get snow any more. :(

[Tom Myers]

So the question: Since WW start out with too high of antimony to get to DanT’s optimal antimony alloy of 97.0 / 1.5 / 1.5, and since I have that 'nugget' of equalizing tin and antimony in my head, I’m wondering if I added 2% tin to the WW I have, would that come close to Tom’s calculations and even-out the tin and antimony, and would that be fit for GG bullets sized .001 over groove? I’m afraid I know part of the answer since these WWs are from the 1960s and reputedly have higher antimony than today’s WWs. But thought I'd ask.

Obviously I’m looking for a way to avoid the expense of buying pure lead or even 16:1 or 20:1. Buying linotype would not be any better on the pocketbook.

To equalize the tin and antimony in your old wheel weights you will need to add 3.5% of the old wheelweight weight in pure tin which will result in the 92.27-3.86-3.86 alloy shown.
Although that alloy makes a very good, tough bullet, it is going to be too hard for traditional BPCR bullets.

http://www.tmtpages.com/LinkSkyImages/forum_images/Alloys/Alloy-Lyman%232-with-wheelweights-and-Tin.PNG

To bring the tin-antimony nugget down to the ideal 97-1.5-1.5 alloy, pure lead will need to be added.

You'r just gonna have to bite the bullet and buy some stuff.
So Weigh your wheel weights and then add 3.5% of that weight of Tin and 163% of that weight of Pure Lead.
or
As the chart shows below, add to a 20 lb pot:
6.75 lb (108 oz)of wheel weights,
1/4 lb (4 oz ) of Tin,
11 lb (176 oz) of Pure Lead
= 18 lb of 97-1.5-1.5 Alloy With an estimated Brinell Hardnes of 10.43 which lies between a 1/20 Tin/Lead alloy BH of 10.15 and a 1/16 BH of 10.53.

http://www.tmtpages.com/LinkSkyImages/forum_images/Alloys/Alloy-BPCR-with-wheelweights.PNG

[Lead pot]

I have a 30 foot catch pile I just made up from the last 12" plus batch we got a couple days ago and I have 60 bullets in it now. I will make a second pile for yours only so they don't get mixed up. Just use a electric pencil and number them on the base for your reference when you get them back. Patch them with your paper and send the wads your using and tell me the specks how you want them loaded.

[SgtDog0311]

Kurt, have enjoyed seeing your samples of recovered bullets.

For you both, it's nice to have the path path shared by those long on it!

i've paid about $.35 a lb for WW. But 40lbs of 20:1 goes fast at $2.50 per. I'll buy it if that's the answer though!

[SgtDog0311]

Thank You Tom!

[SgtDog0311]

From this thread: http://castboolits.gunloads.com/showthread.php?42016-Wheel-Weight-Composition

And this post from User ‘Will’: “Old WWs were about 1% to 2% tin and 9% antimony newer ones have about 1/2% tin. Where the seperation between old and new came was about the 1980s but varied with maker. Best bet is to mix them all together like JohnH said and add a little tin for good fillout..”

With 9% antimony it looks like I might want to just leave this batch of 1960 wheel weights for my smokeless shooting. Guess I’ll smelt a little and then check hardness to confirm what he is telling us. If I got between 10 and 12 bhn then I’d seriously question the 9% antimony that Will claims for pre-1980s WWs.

I am a little skeptical since I’ve never read where WWs give harder than 12bhn but I don’t want to mix up a large batch and find I’ve invested in - then contaminated - a bunch of pure lead and tin needlessly to achieve a DanT optimal mix of lead and Antimony.

Any thoughts or opinions?

[Tom Myers]

From this thread: http://castboolits.gunloads.com/showthread.php?42016-Wheel-Weight-Composition

And this post from User ‘Will’: “Old WWs were about 1% to 2% tin and 9% antimony newer ones have about 1/2% tin. Where the seperation between old and new came was about the 1980s but varied with maker. Best bet is to mix them all together like JohnH said and add a little tin for good fillout..”

With 9% antimony it looks like I might want to just leave this batch of 1960 wheel weights for my smokeless shooting. Guess I’ll smelt a little and then check hardness to confirm what he is telling us. If I got between 10 and 12 bhn then I’d seriously question the 9% antimony that Will claims for pre-1980s WWs.

I am a little skeptical since I’ve never read where WWs give harder than 12bhn but I don’t want to mix up a large batch and find I’ve invested in - then contaminated - a bunch of pure lead and tin needlessly to achieve a DanT optimal mix of lead and Antimony.

Any thoughts or opinions?

John,

You might wish to do some more research concerning the composition of the older wheel weights.

My Third Edition Lyman Cast Bullet Handbook (1st printing - April 1980) lists the composition of wheel weights to be 95.5% - 0.5% - 4.0% with a Brinell Hardnes of 9. (this may be where the 9% number comes from)

Although I do not have the means to verify the actual chemical composition of my stash of older wheel weights, I am able to fairly accurately determine the Specific Gravity of the stash to be 11.01. The actual calculation of the specific gravity of a 95.5-0.5-4 wheel weight alloy is 11.0096.

The specific gravity of a 89.5% 1.5% 9% alloy calculates to 10.590. So I am reasonably confident that my stash of old wheel weights is quite close to the generally accepted 95.5-0.5-4.0 alloy.

I just used my Saeco Hardness Tester to checked some bullets cast from my stash over a year ago. The age hardened bullet returned a Saeco Tester number that is dead on at 8. This converts to a BHN of 13.2. Saeco to Brinell Hardness Conversion Chart (http://www.tmtpages.com/bhchart.htm)
Freshly cast bullets usually test out close to a BHN of 12.

You are quite justified in smelting a small amount of your stash and then testing the results.
Calculations, speculations and theory are never substitutes for hard, real world data.

[SgtDog0311]

I'll sure do more research and testing Tom. I did find yesterday two other sites that mentioned pre-70s composition. Here is one: http://www.tackleunderground.com/community/topic/12664-wheel-weight-alloy-composition/ (see the post by sagacious (http://www.tackleunderground.com/community/profile/14705-sagacious/))

We all know if its on the Internet it's true, right:-)

I have not got a chance to contact beltfedarnie on Shiloh either. Been busy with grandkids and learning about the Vickerman product and getting measurements correct for the 40-65, 38-50 and a 35-40 for ordering. I tell you, working on three projects at the same time while worrying over alloy can tax my brain and my pocketbook. I could say 'when it rains it pours' but "blessing hell" would be more applicable. Got to press on regardless since BPCR and 22 will roll around sooner that I think.

BTW... like BrentD, I reckon I've sidetracked this thread more than is tolerable. My apologies!

[Keith Andersen]

I spend more time reading then posting. This is educational, no need for apologies from anyone.

[Gunlaker]

The one reason I've always kept away from wheel weights is that I don't see why, old or new, there would be any incentive for the manufacturers to use carefully controlled alloys.

Chris.

[SgtDog0311]

Chris, I've always used WWs. But before this year I shot smokeless and just took care to sort well and exclude the new stuff. So now trying to be more selective per all cautions on forums concerning Black Powder.

Cost being relative I'd sure like to use the 600lbs or so that I do have though and not wanting to do a pot at a time here is what I'll do if Tom Myers happens to see this and is willing to proof my math (he knows I'm challenged).

Saw some sheet lead that I have always read is close to pure lead (anyone know if that's true) for these purposes, thought to run down today and pick up what I could at .80cents a lb. Pending what I bring home I calculate as follows.

100 lbs (1600oz) WW
163 lbs (2608oz) lead
3.5 lbs (56oz) tin
=266.5 lbs of Alloy

50 lbs (800oz) WW
81.5 lbs (1304oz) Lead
1.75lbs (28oz) tin
=133.25 lbs of Alloy

25 lbs (400oz) WW
40.75 lbs (652oz) Lead
7/8 lb (14oz) Tin
=66.625 lbs of Alloy

Hope I can find at least 80lbs of pan lead. Looked to have it last night but I was on my motorcycle:-)

[Tom Myers]

John,

Congratulations! You get a GOLD STAR!

Your math looks good.

[SgtDog0311]

Ha!! Thanks Tom. I need GOLD STARS. All done but the work then!

Found 120lbs of thin rolled up sheet. Mighty soft and pliable but I see on the sites that retail this stuff that they offer it with Antimony as well as without.

I'll test the hardness of an ingot before I mix any.

[EDG]

Your time and getting a repeatable alloy may be more important than a few dollars.
Rather than set your goal for cheap metal set your goal for a permanent alloy that you can replicate.
Surely you can find scrap 63 SN 37 PB electronic solder for about $5 to $6 a lb. Then use it to make a BPCR alloy.



OK I have a question for you guys and gals. I used to shoot BPCRS a long time ago.
I'm going to get started again in the spring. Jezzz how things have changed.
I was shocked at the price of tin when I went shopping. I used to buy solder 95/5 for $9 a pound.
It's hard to find around here for under $35 now. I can buy it online for $10+ a pound plus shipping.

OK now the question, I have about 650 lbs of lead and 1200 lbs of lino and mono I bought years ago for .25 a pound. Can I make a usable alloy from this? If so what mix? I do have some tin but not much.
I know you can use pewter for tin but around here they think it's gold.

[SgtDog0311]

I smelted down about 120lbs of the sheet lead. Tested this morning and the debit with the lee tester covers the entire scale .1000, so dead soft. Scale only goes to .079 but extrapolating a .092 would be 4.7 BHN so softer yet! Researching producers sites they make some sheet lead with antimony so wanted to exclude that possibility.
On to smelting the 1960s vintage WW and testing those. I'll report back what my Lee tester tells me.

[M-Tecs]

Words from Dan Theodore ...
My favorite antimonial alloy is the 97.0 / 1.5 / 1.5, which has a BH of 9.8 and took 18 hours to completely age-harden. It has remained at that hardness for over one year

lead/tin/antimony all by weight
97.0 / 1.5 / 1.5 : 7 parts lead + 3 parts Lyman # 2

Q: How do you make #2 Alloy?
A: To make 10 pounds of #2 Alloy, use either of the following recipes: 9 pounds of wheelweights + 1 pound of 50/50 (lead/tin) bar solder or 4 pounds of Linotype +1 pound of 50/50 bar solder + 5 pounds pure lead

I miss Dan. It's been almost two years since he was lost in a house fire.

[Chill Wills]

John, Accuracy is good; when shooting and when mixing lead alloy, However....
You really do not need to hit the alloy ratio on the nose - just have the Sb somewhere in between 1.5-2% and the Sn=1% and not greater than 1.5%

Does that make sense?

Your aged alloy BHN will end up in a narrow range. Even tho the numbers are dependent on measuring device, this mix will yield the correct hardness to hold long unsupported noses from slumping.

-Michael Rix

[SgtDog0311]

I thank you for that Michael!

I tested my pre-1980s WWs (16 hrs after smelting) with a Lee tester: debit with testing die measures .070 or 10.4 BHN. The Lee tester is the only one I’ve used so not sure how accurate my measures are compared to others but that’s what I have.

Also not sure how it changes over time so I’ll continue measuring at 48 and 72 hours.

Given Tom Myers observation that "composition of wheel weights to be 95.5% - 0.5% - 4.0% with a Brinell Hardnes of 9", what does a 10.4 bhn indicate for antimony content of these pre-80s WWs? If I can understand that %age I can move on to the question of how do I get desired hardness/alloy with what I have on hand using the 120lbs of pure lead I recently smelted and this pre-80s stock?

[guninhand]

A good sample alloy (using what you have) for the Money bullets cast in a 20 lb trial pot is the following mix.

3 lbs Lino
15 lbs plain lead
to this add only 1 oz tin

the additional tin will bring the tin total in the pot to about 1%. This is important - do not use more.

This ratio is quick and dirty and will make an alloy of about
97 Pb
2 Sb
1 Sn

It will have a hardness of about 12-13 and be time stable. This will support any BPCR Nose.

You can get out the calculator and scale but this will be close enough.


Used your formula, results perfect. Many thanks for posting.

[Chill Wills]

Used your formula, results perfect. Many thanks for posting.

Thanks for saying so!
(I missed seeing this until now. )

Are you casting for a High Bc bullet and have you shot it in this alloy yet?

[guninhand]

Thanks for saying so!
(I missed seeing this until now. )

Are you casting for a High Bc bullet and have you shot it in this alloy yet?

Am using the Buffalo Arms JIM459560M4, a "Money" bullet, not sure what real BC is, will get two chronos together and measure it for real in the spring. Probably won't get to shoot this alloy before then.

[Tom Myers]

Am using the Buffalo Arms JIM459560M4, a "Money" bullet, not sure what real BC is, will get two chronos together and measure it for real in the spring. Probably won't get to shoot this alloy before then.

Guninhand,

For what it's worth, the Precision Ballistics Software (http://www.tmtpages.com/basbal/bal.htm) contains a feature that makes it possible to quite accurately estimate (As opposed to estimating a BC from bullet profile measurements) an average bullet Ballistic Coefficient between two targets at whatever range distances you can access.

I incorporated this software feature into the Precision Ballistics module after ending up with one chronograph when I started out with two chronographs.
Two important aspects of software vs. chronograph are price and the target range limitation of the chronograph setup.

You would need only a normal muzzle velocity chronograph setup, (The software will calculate the actual muzzle velocity), two targets at any measured range distances with precisely measured vertical group center from aim-point values and a micrometer to accurately measure sight height change between the two targets.

Click here for a Link to the on-line help file page keyed to the "BC from trajectory" feature (http://www.tmtpages.com/Ballistics_Ver-4_Help/hlp_estimate_bc.htm)


http://www.tmtpages.com/Ballistics_Ver-4_Help/bm94.png

[BrentD]

You can also empirically measure (estimate - all things measured are estimates) a bullet's BC with one chronograph by simply measuring velocity of a particular load at two different distances. Simply shoot a number of rounds over the chrony at a near distance until you are confident of your estimate of average velocity and then move the chrony out to a longer, known, distance, and repeat. The two velocities can be then be compared over the known interval in between and a BC is quite accurately produced by the JBM website. The BC's produced this way have repeatedly allowed me to extrapolate from a 200 yds zero to any distance up to 1000 yds within 2 minutes of, and usually less. I typically do this by measuring velocities at 3 yds and 99 yds from the muzzle.

Using one chronograph has advantages (minimization of instrument induced bias) and disadvantages (requires more rounds to be fired), but without question, it works.

[Tom Myers]

You can also empirically measure (estimate - all things measured are estimates) ***************************.

Brent, you are quite correct. It was a sloppy description of the process. I'll amend it.

[guninhand]

Thanks Tom and Brent. I have the Ballistic software and it has a spot for BC calculation as is mentioned for the JBM web page. Was going to borrow a friend's chrony and use it at the safe end and mine at the riskier end, never occurred to me I could get by with just one.

[MaLar]

I used this alloy at the last two shoots I attended. The first was a wash but I expected that after the time I spent away from the discipline.
Had trouble with fouling and other things.
I've got all that taken care of. The last shoot I went to I shot a 20 not the best but I shot 2 animals out of sequence.
Plus the wind was quite strong that day doesn't help I have old peepers now also.
I just cast over 200 of the Lyman 410660 and most all were target grade. This alloy cast very well indeed.

Thanks for your help Chill Wills



A good sample alloy (using what you have) for the Money bullets cast in a 20 lb trial pot is the following mix.

3 lbs Lino
15 lbs plain lead
to this add only 1 oz tin

the additional tin will bring the tin total in the pot to about 1%. This is important - do not use more.

This ratio is quick and dirty and will make an alloy of about
97 Pb
2 Sb
1 Sn

It will have a hardness of about 12-13 and be time stable. This will support any BPCR Nose.

You can get out the calculator and scale but this will be close enough.