Cast bullets labeled .358" 180gr. But weigh 170
- Thread starter dgang
- Start date
Sometimes questions can be answered by plugging them into a little math.
Divide 170 into 180 or 180 into 170 and you will reveal that the weight discrepancy is about 5 1/2 %.
A typical bullet alloy for handgun bullets might be 20 to 1 lead to tin,or roughly 5% Tin.
So,if the tin were absolutely weightless,which it is not,the 5% tin would not cause a 5 1/2 % weight shortage.
I suspect error in calculating the initial volume of the mold...such as not allowing for the shrinkage,or the lube grooves,etc at the drawing board.
It also might not hurt to verify your scale with either test weights,(best) or samples of quality jacketed bullets.
Of course,test weights are best,but not always available.
Generally bullets from Sierra or Nosler or Hornady or Speer,etc,will be very close to advertised weight. Close enough to confirm the scale is pretty good or grossly off. I don't mean 1/10th grain accurate,or even 1 grain accurate,but they will suggest whether a 10 grain discrepancy is the scale or the bullet.
Divide 170 into 180 or 180 into 170 and you will reveal that the weight discrepancy is about 5 1/2 %.
A typical bullet alloy for handgun bullets might be 20 to 1 lead to tin,or roughly 5% Tin.
So,if the tin were absolutely weightless,which it is not,the 5% tin would not cause a 5 1/2 % weight shortage.
I suspect error in calculating the initial volume of the mold...such as not allowing for the shrinkage,or the lube grooves,etc at the drawing board.
It also might not hurt to verify your scale with either test weights,(best) or samples of quality jacketed bullets.
Of course,test weights are best,but not always available.
Generally bullets from Sierra or Nosler or Hornady or Speer,etc,will be very close to advertised weight. Close enough to confirm the scale is pretty good or grossly off. I don't mean 1/10th grain accurate,or even 1 grain accurate,but they will suggest whether a 10 grain discrepancy is the scale or the bullet.
Last edited:
Don Fischer
New member
Melt them down and recast yourself. Problem goes away!
To answer the OP's question: yes, alloy affects weight.
None of my cast bullets weight what the mold says they will. Usually a mold is based on wheel weight alloy or Lyman #2 alloy. It should be indicated with the mold.
Usually, when a bullet weighs less than the mold design, it is due to someone attempting to make one of those stupid hard cast bullets.
Always base your load data on the actual weight of the bullet, not what it is supposed to weigh. That is only common sense.
I you do "melt them down and re-cast them" the problem does not go away. They are still going to cast lighter unless you add some lead to the alloy.
None of my cast bullets weight what the mold says they will. Usually a mold is based on wheel weight alloy or Lyman #2 alloy. It should be indicated with the mold.
Usually, when a bullet weighs less than the mold design, it is due to someone attempting to make one of those stupid hard cast bullets.
Always base your load data on the actual weight of the bullet, not what it is supposed to weigh. That is only common sense.
I you do "melt them down and re-cast them" the problem does not go away. They are still going to cast lighter unless you add some lead to the alloy.
I believe I answered this question on another forum but I'll do it here as well.
Bullet weight cam be noticeably different depending on the alloy used. I have an RCBS mold for the 250 gr. .375 caliber bullet (#37-250-FN) that casts out at 270 gr. in my alloy.
IIRC, RCBS uses linotype metal for determining bullet weight for their molds. Lyman used they #2 metal which probably would be heavier than if linotype were used. My alloy is basically wheel weights with linotype, lead free solder and magnum bird shot added and probably would run somewhere between Lyman's #2 and straight wheel weights.
Maybe the OP should try scratching one of the bullets with a fingernail. If it's a bit difficult to scratch my guess would be it's most likely linotype.
I have a few Lyman #358477 bullets that someone cast out of babbit metal. According to Lyman that bullet should weigh about 150 gr. I know it's close to that with linotype but these very hard babbit metal bullets run right at 141 gr., all because of the high tin content in that particular babbit alloy.
did add just a bit more to this answer from the one on another site. Hope it clears up the OP's question.
Paul B.
Bullet weight cam be noticeably different depending on the alloy used. I have an RCBS mold for the 250 gr. .375 caliber bullet (#37-250-FN) that casts out at 270 gr. in my alloy.
IIRC, RCBS uses linotype metal for determining bullet weight for their molds. Lyman used they #2 metal which probably would be heavier than if linotype were used. My alloy is basically wheel weights with linotype, lead free solder and magnum bird shot added and probably would run somewhere between Lyman's #2 and straight wheel weights.
Maybe the OP should try scratching one of the bullets with a fingernail. If it's a bit difficult to scratch my guess would be it's most likely linotype.
I have a few Lyman #358477 bullets that someone cast out of babbit metal. According to Lyman that bullet should weigh about 150 gr. I know it's close to that with linotype but these very hard babbit metal bullets run right at 141 gr., all because of the high tin content in that particular babbit alloy.
did add just a bit more to this answer from the one on another site. Hope it clears up the OP's question.
Paul B.
Thanks for the input
I did do a crude hardness test, nail punch and 8oz. hammer from 6", with a known hard cast bullet ( Laser Cast, about 15 bhn according to the new owner Frank) and they appear to be about the same. NBC bullets (sorry not ABC) use to brag about their hardness. I agree, even with a large amount of alloy it would not account for the difference in weight. I will load accordingly. Thanks again.
I did do a crude hardness test, nail punch and 8oz. hammer from 6", with a known hard cast bullet ( Laser Cast, about 15 bhn according to the new owner Frank) and they appear to be about the same. NBC bullets (sorry not ABC) use to brag about their hardness. I agree, even with a large amount of alloy it would not account for the difference in weight. I will load accordingly. Thanks again.
Mauser rifles were the first to use a cartridge clip to charge bolt action rifle magazines. The USA paid royalties to Mauser in 1902 to use the same system in M1903 rifle designs. John Garand called his 8 round cartridge holder a clip. Oft times called an "enbloc" clip. Browning, Colt and S&W have called them magazines for decades. Revolvers use half-moon clips. The first semiautomatic pistols by Luger and Borchardt used magazines. The 40mm Bofors twin and quad heavy machine guns I aimed and fired from my GQ station on a USN destroyer in the late '50's were reloaded with clips of 4 rounds previously stored in magazines.Agree with you on the use of the word "clip". John Browning referred to the "loading device" on the Model 1911 .45 as a "clip". If it was good enough for Browning it is good enough for me.
That's why "clip guide (slot)" is the name of the rifle receiver bridge cutout a clip fits in to align the cartridges to charge the magazine. M14 rifles and bolt action NRA match rifles have one to help charge their magazines.
From SAAMI's glossary:
CARTRIDGE CLIP
A separate cartridge container to hold cartridges or shells in proper sequence for feeding into a specific firearm. It is a magazine charger, and unlike a magazine does not contain a feeding spring. Sometimes improperly called a Magazine.
Last edited:
Jim Watson
New member
I have not heard anybody improperly call a clip a magazine.
Of course calling a magazine a clip is a common error that arouses the ire of the internet experts who think the "bore" of their rifle is .308".
Of course calling a magazine a clip is a common error that arouses the ire of the internet experts who think the "bore" of their rifle is .308".
I admire your attitude about learning the difference.Bart B: I stand, if not corrected, at least more educated.
The cast bullets hardly ever weigh what is listed on the mould casting them...
My answer is...Don't weigh them and use data listed for the weight on the box.
But this is with home cast bullets.
Store bought cast bullets , 10 grains off is a bit much . Some where along the highway a mistake was made by packaging or labeling or casting .
Weigh them and load as 170 grain . If data is hard to come by ...using data for 180 grain bullet will be safe .
Gary
My answer is...Don't weigh them and use data listed for the weight on the box.
But this is with home cast bullets.
Store bought cast bullets , 10 grains off is a bit much . Some where along the highway a mistake was made by packaging or labeling or casting .
Weigh them and load as 170 grain . If data is hard to come by ...using data for 180 grain bullet will be safe .
Gary
Per above. Mike em. That tells you a lot.
Used to be a punch tool to give you an idea (not perfect) for hardness and maybe not a bad idea to have one if they still exist if you are going to work with cast.
And from memory, I read accounts of the variations in cast so it does not sound like they are wacko off, though 10 grains would seem to be abut the max (for 180 gr weight) .
Used to be a punch tool to give you an idea (not perfect) for hardness and maybe not a bad idea to have one if they still exist if you are going to work with cast.
And from memory, I read accounts of the variations in cast so it does not sound like they are wacko off, though 10 grains would seem to be abut the max (for 180 gr weight) .