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View Full Version : Does boolet alloy expand or contract



Grandpa Dolan
06-26-2006, 11:41 AM
There must be a lot of Boolet makers out there with experience on Boolet Dia..This happened to me. I ordered an Aluminum mold from NEI It is marked 318 175. It does not make '318 Boolets. It makes .324 Boolets.....I was Told by NEI that there is a .003 tolerance and that my alloy expands .002 when casting and cooling. .002 expanssion is not my experience. Matter of fact I have measured a contraction of about .002 on a 311 Dia. paper patch Boolet. May I ask has any one ever measured this sort of thing??? Thanks Grandpa Dolan Takke time to play......

felix
06-26-2006, 12:17 PM
Only lead having antimony will expand. All other "lead" contracts. ... felix

StarMetal
06-26-2006, 01:51 PM
Felix I believe that is wrong. Lead can be mixed with other unique metals to make it expand upon solification like bismuth. Its unusual property to expand upon solidification makes it useful in type-metal alloys and for castings. The most important use of bismuth is in the manufacture of low-melting alloys which is used in electrical fuses and in automatic fire alarm and sprinkler systems. For these uses bismuth is mixed with lead, tin or iron to form fusible metals, which melt at low temperatures.

Joe

felix
06-26-2006, 02:00 PM
Yes, Corky and I mix bismuth in our alloys to gain weight, not to expand during aging. Antimony does the latter chore. Bismuth will expand lead somewhat, but almost never over the "casting" diameter unless antimony is present. ... felix

StarMetal
06-26-2006, 02:08 PM
It's in Pepto Bismo too!!!!!!!!!!

Joe

ANeat
06-26-2006, 05:48 PM
Pure lead will shrink the most. Lino will cast pretty close to the size of the mold. WW, Lymans #2, and other alloys are somewhere in the middle as in some shrinkage but less than lead.

When I had Ballisti-Cast make me a mold they wanted to know the size I needed for the finished bullet and the alloy I will be using. A mold to cast a specific size for Lino will throw a smaller bullet in WW and even smaller still in pure lead.

Another thing you can look at with your bullet is the weight. I would be curious as to what alloy you are casting with and with your 318/175 mold what the weight of the bullet is.

If you can get by with a softer alloy you can cut in some lead with it to get closer to your spec diameter.

Adam

LET-CA
06-26-2006, 07:49 PM
It's my understanding that your casting temperature will also play a part in how much shrinkage you experience. The hotter you cast, the more shrinkage.

Bucks Owin
06-27-2006, 09:57 AM
FWIW, I think lead "springs back" slightly when it's sized too.....
(about .0005" in the case of my .357" sizer...)

Dennis

NucEm
06-27-2006, 11:40 AM
Felix, you talked about bismouth. Never tried that, how about casting with only that?
And how much do you mix now in your aloy? Any special things ones has to do when doing that? lots of questions[smilie=1: but i only use ordinary stuff in my casting, anything "new" translates to "must try" for me so share some info if you have:drinks:

felix
06-27-2006, 11:53 AM
Good idea, if you can find some cheap. Bismuth is harder than antimony, and heavier than lead. Those parameters make bismuth an ideal material to play with. The downside is the expense, and it's brittleness. Best to use it like you would antimony. If you find some pure, which is doubtful, mix it with pure tin at 50-50 by volume, and add that to your boolit material on hand as if you were augmenting the boolit material with pure tin only. ... felix

felix
06-27-2006, 11:59 AM
Dennis, lead does not spring back. Only a tougher lead mix will do that. Ideally, you want as much springback as you can get, meaning that you have the toughest boolit possible with the components in the mix. Keep in mind that a hard boolit and a tough boolit do not necessarily correlate as you would think. Ideally, you only want only the lube to strip so the boolit only slides, with the lands punching into the body of the boolit. A perfect boolit (impossible?) would never show land marks, nor tail fins. ... felix

Bucks Owin
06-27-2006, 02:36 PM
Dennis, lead does not spring back. Only a tougher lead mix will do that. Ideally, you want as much springback as you can get, meaning that you have the toughest boolit possible with the components in the mix. Keep in mind that a hard boolit and a tough boolit do not necessarily correlate as you would think. Ideally, you only want only the lube to strip so the boolit only slides, with the lands punching into the body of the boolit. A perfect boolit (impossible?) would never show land marks, nor tail fins. ... felix

This is 50/50 WW and printer's linotype and comes out of a .357" size die at closer to .358"....

It's very hard and groups under 2" with most loads at 25 yds. With Lar45 Carnuba Red I get almost zero leading. I would like to try a .358 sizer though just for fun....There are a couple of J bullets that do a little better, can't have that! :D

Dennis

Dale53
06-27-2006, 04:57 PM
All "typical" lead alloys shrink after casting upon cooling. Some just shrink less than others (pure lead the most, with lino shrinking the least of the common bullet alloys). If the alloy did not shrink, or worse, expanded after casting, you would NEVER get it out of the mould without melting. Shrinkage is what allows you to get the bullets out of the mould.

When sizing bullets, pure lead tends to NOT "spring back" after pushed through the sizer. Varying amounts of antimony allow some "spring back" - the harder the alloy, the more the "spring back" which can give you bullets slightly larger than the hole that they were pushed through.

FWIW

Dale53

Grandpa Dolan
06-27-2006, 08:28 PM
Yes thank you all for the information. From my measurements, I tend to agree with you ,Dale 53. Lead alloys contract when they cool. I just cannot get measurements with hi lynotye alloy indicating very much expanssion from the inside Dia of the mold. I have a 311332EM Lyman mold. It is a "paper patch mold", with straight sides useing plug gauses and "inside compass and micrometer" methods I consistantly get an inside Dia of .313. Yes Felix almost pure lead gives boolets .311 in Dia. I do agree with you and others that pure or almost pure lead does contract. My problem is the same mold with an aloy of almost pure monotype does not expand the .002 we expect when cool. I am told by many it should. I find it hard to measure any. Iwill get some pure Lynotype soon and check that . Agan thank you all for your comments. I will keep the .318 mold I got from NEI. and use the .324 boolets in one of the 8 mm. I have. It does make good boolets. Take time to play,, Grandpa Dolan

Bucks Owin
06-27-2006, 11:35 PM
So, like I said, the 50/50 lino alloy "springs back" .0005+" after sizing...[smilie=1:

Dennis

BTW, just out of curiosity, if I were to size them a second time would they be more likely to stay at .357" than they do with the first size down from .359" to .360" as cast?

Doughty
06-28-2006, 10:04 AM
Bucks,

Another thing to remember is that just because the die says ".357" doesn't mean that is exactly what the diameter of the die is. You might try sizing some soft "pure" lead and then some hard lino and see what the variance is. I don't know what alloy the big manufacturers use to "calibrate" their dies. I always just assumed that Lyman used Lyman #2. Using plug gauges, I've had dies marked .357 vary from .356+ to .358+.

Dale53
06-28-2006, 02:31 PM
Old Vic;
>>>just because the die says ".357" doesn't mean that is exactly what the diameter of the die is.<<<

Good point, Vic.

Another point is that not everyone can measure lead and lead alloys correctly. I don't mean to try to put any one down, but not everyone is a machinist. Some people just can't read a micrometer correctly (it is a learned skill) and dial calipers are really not good enough when you are talking one thousandth of an inch. A good man with a micrometer can reliably read a micrometer in ten thousandths of an inch. It cannot be done reliably with a dial caliper due to the fact the calipers are not rigid enough. There is a lot of "feel" involved when trying to "mic" soft alloys...

I have seen this "lack" demonstrated many times. I was trained as a machinist and my father, whom I worked with for many years before going out on my own, was a high grade tool maker (jig and fixture man in the aircraft industry).

Just a thought...

Dale53

Bucks Owin
06-29-2006, 01:54 PM
Well, FWIW, I've had plenty of experience in reading a mic (been a mechanic for decades) and use the spring loaded screw on my Starrett mic (which reads to .0001") for consistent readings. A .357" J bullet slips through the die easily, a .358 WC doesn't. In MY view, FWIW, these hard boolits do "spring back" a half a thou' when sized...

Believe what you like, I'll believe the mic!

Dennis

StarMetal
06-29-2006, 02:33 PM
Dennis,

Well then you now that measurements should be taked when the object is at the same temperature when they are taken, right?

Joe

Bucks Owin
06-29-2006, 03:15 PM
Dennis,

Well then you now that measurements should be taked when the object is at the same temperature when they are taken, right?

Joe

Yep...

Maybe someone besides me should try a hard lino mix and do a little miking themselves? Hmmmm? [smilie=1:

Dennis :Fire:

StarMetal
06-29-2006, 03:50 PM
I don't have too, I know they spring back.

Joe

Bucks Owin
06-29-2006, 04:07 PM
I don't have too, I know they spring back.

Joe

;)

Dennis

kywoodwrkr
07-01-2006, 05:59 PM
Lyman addresses this in a table in one of their cast bullet manuals.
Various calibers, various compositions,as cast and after sizing.
Wasn't a cast manual after all.
Was Reloading Handbook #46.
Example
8mm #323470
Lead 167 gr .3234" cast size
W-W 165 gr .3240" cast size
#2 Alloy 160 gr .3245" cast size
Lino 155 gr .3248 cast size
H&I Sizing die .323
lead sized to .3226"
W-W " .3227"
#2 Alloy .3230"
Lino .3233"
FWEIW