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Old August 18, 2002, 12:11 AM   #1
Blue Duck357
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Cast bullet weight disparity

Just playing with my new scale and Laser cast "158" grain SWC bullets. My scale shows zeroed fine on the check weights, but all my bullets are showing up 155.2 to 155.6 grains instead of 158.

Now I know 2.8 grains less is certainly not going to affect how hard they hit the paper I shoot or a .4 grain weight range is not really going to throw my groups off that much. Just wondering if these variances from posted weight and weight range are normal/good/bad?
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Old August 18, 2002, 12:42 AM   #2
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I'd say your finding is normal for Laser-Cast bullets. Almost all of the L-C bullets I have weigh from 1 to 3 grains under their nominal weight. For example, I have some "148 gr." DBWC's that are actually 145 gr. The weight range for your lot is good. Some manufacturers will have a much wider range than you found. You can safely ignore the variations. You and I would have to be extremely fine shooters and shooting extremely fine guns before we could tell the difference the bullet weight variances are making.
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Old August 18, 2002, 07:42 AM   #3
C.R.Sam
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The deviation you found between bullets is great.

All being lighter than nominal is normal.

Designated weight of cast bullet based on lead.

A mould that throws 158gr lead will throw lighter bullets when the lead is alloyed with tin, antimoney, marigold etc.

Sam
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Old August 18, 2002, 09:32 AM   #4
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BAD BULLET MOJO

So a friend bought a name-brand cartridge for shooting at a major USPSA match, and when the ammo got to the chrono stage it made Minor due to its bullet weighing 216g instead of 230g.

Winchester Lead-Free.
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Old August 18, 2002, 09:58 AM   #5
Mal H
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Wow! That goes far beyond "small variations in weight". I'll bet the powder load was correct for 230 gr. which means it was a light load for a 216 gr. Double whammy.

Blue Ducks bullets are less than 2% low, those are 6% low.
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Old August 18, 2002, 10:48 AM   #6
C.R.Sam
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If power factor is going to be a factor...
Check your ammo PRIOR to going to a match.

Sheesh.

Sam
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Old August 18, 2002, 12:00 PM   #7
AC
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those are good bullets

There is a very slight variance in weight from bullet to bullet. Swaged slugs are more uniform because there are no voids. Your cast bullets aren't showing voids either, or if present, very small ones.
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Old August 18, 2002, 12:23 PM   #8
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Difference between 'think' and 'know'

Kinda new shooter; first big match.
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Old August 18, 2002, 01:45 PM   #9
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Lyman molds state the weight from the mold is from Lyman #2 Alloy which is NOT pure lead. I don"t know about other mold makers. Quantrill
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Old August 18, 2002, 04:09 PM   #10
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It all depends on the alloy.

I have a H&G mold for a "240 gr." .41 Magnum bullet. It throws a 230 gr bullet cast of wheel weights, and a 225 gr bullet cast of lin-o-type. The weight is specified for Lyman #2. Wheelweights are heavier and lin-o-type lighter.
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Old August 19, 2002, 02:10 PM   #11
TGS
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.5 gr. variation

Ive bought various makes of cast bullets and always sort. Ive wondered what type of variation came along with L/C's. If what your saying is typical its money well spent. I have found that a box of other than L/C's (500) would have a range up to as much as 5 grains. and as much as 15 grains from nominal. Your L/C's are excellent. I have never tried L/C's!
There is a lot of information about cast bullets and bullet casting www.loadyourown.com enough to get me into doing just that.
Alloy consistancy (lead tin antimony %'s), cast temp, iorn or aluminum molds ( I am using aluminum to start with).
I have found that lower s.d. most often yeild tighest group but its sure not carved in stone. Lower s.d. are accomplished with the least amount of variation accross the re-loading process. I have definitely measured the difference. If all my bullets in the string vary less than .1grs and another string varies from min to max .9, everything else being equal, the .9 string will have a higher s.d and the group will more often than not be greater.
Just stands to reasn that the less variation in a process the more predictable the results will be. Primers also play into it. Ive made up strings with all elements equal and yeilding my lowest s.d then use 4 different primer mfg's and the s.d. goes out the door. I try to cast my bullets with .5gr max variation and I have not yet been successful using a six cavity mold when moulding 300 - 500 bullets. If I use one cavity, with no change in alloy, no change in temp, or cadence it has happened.
Bullet casting gets very addictive as does the use of a chrono. Be sure though...if you keep down the variation you keep down the cost. What I like about casting my own is if I dont like them...melt them
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