Bullet weight, 10 grains more or less . . .

P

Prof Young

New member
Loaders:

I bought a whole bunch (2000) of 115 gn coated bullets from Missouri Bullets. They are weighing in 7 to 9 grains less than 115. I'm guessing this does not make all that much difference for target shooting/plinking loads, but thought I'd check with those of you who know more about this stuff than I do.

And just FYI, following formulas in the Lee manual, 4.1 grains of Titegroup was kinda hot. A bit more than I want for target shooting. Backed it down to 3.7 and while still hot it was better.

Talk to me please.

Life is good.
Prof Young
 
Is this for 9mm? If so, I load 9mm with 3.2 grains of Titegroup. Functions flawlessly in my Beretta 92FS with factory recoil spring.
 
The actual weight of a cast bullet will vary from the nominal weight according to the composition of the lead alloy being cast. Pure lead bullets will be heavier than bullets cast from wheel- weights using the same mold. Adding a little extra tin increase your bullet's hardness will make them even lighter.
 
^^^^^^^^Yah, that. Back in the day I hauled around 900 pounds of around 12% "linotype" printing metal away from a local printing firm that was changing over to a more modern process. Hard metal that cast into some very nicely moulded .45 Colt Keith style semi-wad cutter bullets. That lead rang like a bell when hit with a hammer, it was so hard.
But, as posted above, they came out of the mould a bit lighter than the 255 grain bullets did when using the #2 Lyman lead alloy ingots.
I just started at the low end of what the loading manuals recommended and eventually got to the 8 grains of Unique powder that Skelton recommended in his Colt SAA revolvers.
 
Out of spec

Prof Young,
When I bought my first several boxes of coated bullets from MBC, I would weigh each bullet in a box of 500. These were 200 gr .45s. The weight was generally between 198.0 - 203.0 grns. I emailed MBC who responded that their target was +/- 10% of the stated weight. Mine were well within that goal. My estimation is that 80% or more were between 199.0 - 202.0. My experience with .38s is the same, within +/- 2 grns. Extreme (plated), and Bayou are about the same. The only exception were Hornady FMJ-match bullets for .223 where 98 out of 100 were within 0.1 grns. I've tried shooting groups with bullets which were +/- 0.05 grns, but found no difference, probably due to my limited skills.
 
Often the claimed weight is what the mold maker said the mold was supposed to produce, so, yes, alloy density and coefficient of expansion and crystallization shrinkage and exact casting temperature all affect the actual weight. Having designed molds using CAD software to keep track of the volume, I can tell you the mold maker's allowances also affect what you actually get from your alloy as well.

The old target shooter's rule of thumb was to use bullets within three grains of extreme spread and reject others, especially lighter ones. This was based on 148-grain .38 wadcutters, so it is a span of about 2% or ±1% from the mean, whichever way you want to look at it.
 
I agree with what Pathfinder said. The weight will depend on what material was use to make the alloy. I cast my own bullets with an alloy mix that works for me. Bullets come out a bit heavier than what the mold designed said it should weigh but I get nice cast bullets and they work for me.
Paul B.
 
The old target shooter's rule of thumb was to use bullets within three grains of extreme spread and reject others, especially lighter ones. This was based on 148-grain .38 wadcutters, so it is a span of about 2% or ±1% from the mean, whichever way you want to look at it.
Click to expand...

I saw an interesting take on that once.

Assuming homogeneous lead and the mold not gapped open by flakes of lead or bent by whacking too hard with the sprue mallet...
If the mold is well filled out, then that will be the heaviest bullet possible. A lighter bullet has a void or a rounded band. So you should shoot the heavy end of your sort, not the average.
 
That's right. I think the rule is premised on multiple mould cavities not all producing the exact same bullet weight and also on the idea the bullets cast while the mold is still warming up will be a little light, but not necessarily unbalanced, so they may shoot fine.
 
My only experience casting good quality bullets was for BPCR. Light bullets from warmup or whatever else were NOT considered worth even loading.
 
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