Author Topic: No more bullet weight info needed.  (Read 677 times)

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Offline joeb33050

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No more bullet weight info needed.
« on: January 13, 2005, 02:31:03 AM »
All the visually perfect bullets properly cast during one session will weigh within half a grain of the average, or less; frequently within three-tenths of a grain. If they don't, you're doing something wrong.
This is without regard to the average weight of the bullet, based on my records that cover 7348 bullets, cast 111 per average session, with average bullet weights from 58 to 445 grains.
The average standard deviation of all sets of bullets cast was .139 grains.
For some reason the distribution of cast bullet weights is independant of average weight, a statistical situation that I don't understand. Like so many things.
This holds true where I don't stop for a break, or add alloy to the pot reducing the temperature a lot, or do anything else unusual-just a straightforward casting session.
When I weigh cast bullets, and I weigh almost every one, I throw out any beyond half a grain from the mean. There are perhaps two or three of these in an average set of 111 bullets cast.
Information about bullet weights from Pete and 40 Rod confirm this.
Since we now know, no further information is needed.
joe b.

Offline Dusty Miller

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« Reply #1 on: January 13, 2005, 10:53:20 AM »
Well, I guess that's the final word on this topic.  Admin. can just lock it up (in case some absolute BOZO thinks he might have just a little something to add!).
When seconds mean life or death, the police are only minutes away!

Offline Longcruise

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« Reply #2 on: January 13, 2005, 04:17:35 PM »
Quote
(in case some absolute BOZO thinks he might have just a little something to add!).


Heh Heh, I'll bite!! :)

Quote
I throw out any beyond half a grain from the mean.


IMO, what you should be doing is throwing out anything that is less than half a grain from the max the mold can throw. :twisted:

Offline joeb33050

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« Reply #3 on: January 14, 2005, 01:30:39 AM »
Quote from: Dusty Miller
(in case some absolute BOZO thinks he might have just a little something to add!).

I didn't know that there were any absolute BOZOs on this forum.
joe b.

Offline Dusty Miller

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« Reply #4 on: January 14, 2005, 05:58:08 AM »
OH! Joeb!  Absolute Bozos abound!!  There's nary a nook or cranny of American society that does not have an AB or two lurking about! :P
When seconds mean life or death, the police are only minutes away!

Offline Greybeard

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« Reply #5 on: January 14, 2005, 06:04:08 AM »
Sure is nice that we have such an expert to grace the site and explain to us all that we're doing it all wrong and have been for the past 40 years. Oh well maybe we should just all stop casting since we don't really know how anyway.  :)


Bill aka the Graybeard
President, Graybeard Outdoor Enterprises

Offline Dusty Miller

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« Reply #6 on: January 14, 2005, 09:17:47 PM »
Hey Greybeard, THIS absolute bozo (according to my wife!) has been casting for ten years and will continue to do so no matter HOW MANY other ABs show up!!
When seconds mean life or death, the police are only minutes away!

Offline joeb33050

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« Reply #7 on: January 15, 2005, 02:02:10 AM »
Quote from: Greybeard
Sure is nice that we have such an expert to grace the site and explain to us all that we're doing it all wrong and have been for the past 40 years. Oh well maybe we should just all stop casting since we don't really know how anyway.  :)

I don't read that anyone said that you're all doing it wrong. I've been doing it for 44 years, and wanted to know what to expect for cast bullet weight variation. I went to the forums and asked for info. I took my info, and contributed info, and analyzed it to get the result in the message. If you don't want to believe it, don't. If you have anything of substance to offer, offer. If you want to be snide, be snide, cause this is the good old U S of A, where anyone can say anything he wants, no matter how wrong.
joe b.

Offline Dusty Miller

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« Reply #8 on: January 15, 2005, 07:10:40 AM »
Hey Joeb, don't be so reticent man, speak up!  Do you or do you not think you are RIGHT on this issue?!!
When seconds mean life or death, the police are only minutes away!

Offline unclenick

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« Reply #9 on: January 15, 2005, 08:44:38 AM »
Hey Dusty, if you think your wife is the absolute expert on detecting AB's, we should put her into a challenge match with my wife, who appears to me to the expert.  
   
Actually, I find Joeb's information fascinating.  It makes no intuitive sense to me that it should be true.  You would expect that errors in weight due to mold temperature variation would be proportional to the volume of each cavity.  You would expect errors due to mold closing would be a two DOF function of profile area and profile length (out-of-round error and feathering, respectively).  You would expect geometric errors to be proportional to alloy density if you replicated them with different alloys.  The whole thing is weird.  It's as if there were a tendency for different error types to to compensate for one another in some way, but I can't imagine what that would be?  
   
So, naturally, questions arise:  The premise of Joeb's point seems to be: if you are doing everything right, this results.  Soooo, acid test, how do bullets meeting this criteria shoot compared with those that don't?  One would presume a .457 bullet could tolerate greater weight variation than a .224 bullet before the effects show up on the target.      
   
I now routinely drill and tap a short blind hole in a corner of my mold blocks to accept a thermocouple trapped under a screw (aluminum screw for aluminum block, steel for iron blocks).  This lets me use temperature to time pours.  It does a very good job of keeping bullet dimensions consistent.  Joeb's data indicates that, should I raise or lower the mean mold temperature I pour at, the cast weight variation would remain the same.  Very unexpected, if true.  
   
A second set of questions pertain to a portion of the premise, that the bullets be "visually perfect".  If you try both bottom pour and ladle pour methods, you quickly see a difference in the filled appearance of the bullets. Because the velocity of the molten alloy from a full bottom pour pot is higher and puts more inertia into the lead, it tends to yield sharper fill details.  Even so, the bottom pour bullets aren't more accurate.  "Constancy is insight", according to Lao Tzu, and, as we all know, it is what produces cast bullet shooting performance.  Also, some alloys fill molds better than others, regardless of pour method.  So then, what defines "visually perfect" in this context?  Is it just consistent appearance?  Does it change with alloy and production method?  If you do accept a change for alloy and method, does that change the distributions and standard deviation in weight?      
   
Joeb, do you have any additional information about the alloys and casting temperatures and pour methods involved so we can see if there is any pattern there?  Or have you already made that comparison?  Like you, I don't see a reason your numbers should be true, but we can't just shoot the data.  Well, OK, maybe we could, but you know what I mean.  
   
Thanks,  
Nick

Offline joeb33050

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« Reply #10 on: January 16, 2005, 01:25:12 AM »
Quote from: unclenick
 
   
So, naturally, questions arise:  The premise of Joeb's point seems to be: if you are doing everything right, this results.  Soooo, acid test, how do bullets meeting this criteria shoot compared with those that don't?  One would presume a .457 bullet could tolerate greater weight variation than a .224 bullet before the effects show up on the target.

 

This wili require some actual testing. Shooting would be involved, as well as record keeping and some of the dreaded statistics. This is my next test.


   
   
I now routinely drill and tap a short blind hole in a corner of my mold blocks to accept a thermocouple trapped under a screw (aluminum screw for aluminum block, steel for iron blocks).  This lets me use temperature to time pours.  It does a very good job of keeping bullet dimensions consistent.  Joeb's data indicates that, should I raise or lower the mean mold temperature I pour at, the cast weight variation would remain the same.  Very unexpected, if true.


Perhaps you might experiment and tell us if bullet weight is a function of alloy temperature.
 
   
 So then, what defines "visually perfect" in this context?  Is it just consistent appearance?  Does it change with alloy and production method?  If you do accept a change for alloy and method, does that change the distributions and standard deviation in weight?

Visually perfect means what it says. Any rounded should-be-sharp edge, or any defect is cause for rejection. This under a 4X magnifier. The only difference in appearance is that high lead/antimony alloys start to have a pattern of dark spider-web kind of stuff on them, but it's only skin deep.

     
   
Joeb, do you have any additional information about the alloys and casting temperatures and pour methods involved so we can see if there is any pattern there?
 



I use a ladle, the alloys range from mostly wheelweights to some pretty hard monotype-ww mixes.

Offline carpediem

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Thermocouple?
« Reply #11 on: January 16, 2005, 09:34:26 AM »
Hello All:

What the heck is this about a thermocouple being installed in the mold for consistancy of heat?

Please explain how you have done this and what the thermocouple does and how you get the reading.  A picture would be nice.

Kindest regards,
The most absolute bozo, Max
Carpediem