Lead Alloy Modifications to adjust diameter of cast bullets

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SpanishPeacock
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Lead Alloy Modifications to adjust diameter of cast bullets

Post by SpanishPeacock »

Hoping to see if I can increase the diameter of my 38-50 Money Bullet slightly by changing the lead alloy mix. Currently the BACO mould drops the bullets at bore diameter, but would like to increase it by at least 0.001". I tried increasing the temperatures of the mould and lead, but only succeeded in creating unacceptable finning. Do I increase the pure lead concentration or do I add more alloy mix, i.e. tin, linotype, etc? Currently my BHn is 12.
Any reference materials or comments on this subject will be appreciated.
Regards,
craneman
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by craneman »

The money bullet has shown a definite improvement in accuracy when using 16-1 alloy or harder. The two options I see for you are to order a mold the diameter you want and sell this one or you could lap your present mold to a larger diameter. I would personally choose the first but to each his own. I don't mind lapping a cheap Lee mold but am always hesitant to do so with a quality mold like the BACO.
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powderburner
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by powderburner »

http://www.lasc.us/CastBulletNotes.htm
At the bottom of this page is a comparison of alloys and their sizes
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desert deuce
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by desert deuce »

Don't know much about casting for the 38-50. But, am about to begin that journey, grandchildren you know.
Anyway, finning from my experience is usually caused by too much pressure on the alloy when injecting the cavities and occasionally suspect that too hot of a mould or alloy or both may contribute but for sure too much pressure on the alloy when the alloy and mould are up to temperature will do it, as will the mould block faces not completely mated or sprue plate improperly adjusted.

Also, when slugging the bore to determine groove diameter do you slug the four inches at the muzzle last or only?

Jim at BACO can make whatever you need IF he is provided the correct dimensions.
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George Babits
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by George Babits »

Somewhere I have seen some data on the diameters of specific bullets cast with different alloys. It might have been in the archives here. At the time I was trying to bump up the diameter for an original 38-88. IThe data I saw gave the following for the Lyman 375449 bullet mould as follows:
pure lead; ` ,3773 inches, 276 grain weight
wheelweight; .3779 inches, 272 grains
#2 alloy; .3785 inches, 264 grains
linotype; ,3789 inches, 256 grains

The source also had data for other bullet moulds, but the other bullets pretty much followed the above example.

George
SpanishPeacock
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by SpanishPeacock »

Thank you! Looks like your reference confirms that additional alloy mix, i.e. harder alloy, will increase the diameter slightly with a corresponding lower weight. I will go with that thought and see what results. Maybe a BHn 13 is all I will need.
Thanks again
SpanishPeacock
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by SpanishPeacock »

SpanishPeacock wrote: Thu Nov 03, 2022 10:54 am Thank you! Looks like your reference confirms that additional alloy mix, i.e. harder alloy, will increase the diameter slightly with a corresponding lower weight. I will go with that thought and see what results. Maybe a BHn 13 is all I will need.
Thanks again
Looks like "PowderBurner's" reference to LASC posting also confirms that the harder alloys have less shrinkage; therefore, larger as-cast diameters.
Thank you all for the help.
ian45662
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by ian45662 »

SpanishPeacock wrote: Wed Nov 02, 2022 7:25 pm Hoping to see if I can increase the diameter of my 38-50 Money Bullet slightly by changing the lead alloy mix. Currently the BACO mould drops the bullets at bore diameter, but would like to increase it by at least 0.001". I tried increasing the temperatures of the mould and lead, but only succeeded in creating unacceptable finning. Do I increase the pure lead concentration or do I add more alloy mix, i.e. tin, linotype, etc? Currently my BHn is 12.
Any reference materials or comments on this subject will be appreciated.
Regards,
When you say bore diameter…. Do you mean the groove diameter or the actual land to land diameter?
SpanishPeacock
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by SpanishPeacock »

Bore diameter = bottom of the rifling lands = .377" Do I have the nomenclature wrong?
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by bobw »

Bore dia is top of the lands . groove is widest dia.
bobw
SpanishPeacock
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by SpanishPeacock »

I stand corrected, thank you. Groove diameter = .377" and the current BACO mould does drop them at "Groove diameter". Looking to see if a little wider will shrink the groups at 300 meters.
Thanks again
ian45662
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by ian45662 »

I’m not trying to be nit picky but if you were wanting bore diameter bullets I was going to give you some advise but I don’t do much in the way of groove diameter bullets so I can’t offer much info other than when I was experimenting with various alloys for my paper patch stuff I didn’t notice very much change at all in the diameter of the projectiles. I was looking for it since it was supposed to change with different alloys but I just couldn’t detect it.
SpanishPeacock
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by SpanishPeacock »

No worries, I am experimenting and hoping for a small increase in diameter, if any at all. The new load will use the harder bullets, BHN 13. If nothing else, it may help with the long range groups. The recommended alloy is 16:1, so I am close to that with the new mix. We shall see.
Thanks to everyone for the guidance and comments.
Regards,
Kenny Wasserburger
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by Kenny Wasserburger »

Best to figure out what you’re really wanting.

As in Groove vrs Bore Diameter.
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Kenny Wasserburger
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Re: Lead Alloy Modifications to adjust diameter of cast bullets

Post by Kenny Wasserburger »

Sorry,

Forgot to add: Once you know what you want then order the proper size mould.

KW
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