How much difference in weight is too much?

[jwlegal]

I have cast handgun boolits for a long time, but did not do much with rifle boolits till I read a lot in this forum. Seems rifles can be just as accurate with lead as with copper when done right. But the question keeps coming up. What is "done right."
With handgun boolits mostly for practice a grain one way or the other doesn't seem to make much difference. With rifles, I'm not so sure. Took a long time to get the hang of them little bitty critters in the first place. A 45 is pretty easy. A 30 caliber boolit is a horse of a different shoe size.
But once they are coming out of the mold the way they should, how much variance in weight is acceptable before it really begins to make a difference at 100 yards?
Sat down and weighed some commercial 45 boolits. Just grabbed a few from a maker that sold by the box of 100 and they ranged between 184.3 to 185.3 for their 185 gr. 45 ACP cast boolit. Another that sold by the box of 500 for a 200 gr.45 ACP ranged from 193.1 to 197.5. Didn't weigh them all but none I found actually weighed 200 gr.

Then I got out a few j-word projectiles and one .30 cal 180 gr. box weighed from 179.6 to 180.9
Another 200 gr. 30gr. 30 cal ran 199.2 to 201.5

Finally tried a few of the solid copper gizmos and for 200 gr. in 30 cal I found 199.8 to 200.5
in 180 gr. 30 cal solid copper I found the best running from 180 to 180.3

So, in the 45 handgun mass casting boolits there was a 1gr difference in on brand and a 4.4 gr difference in the other

In commercial j-word projectiles there was a 1.3 to a 2.3 gr difference

In commercial solid brass there was an allowance of .7 in one and .3 in the other.


I have always tried to stay within .5 gr plus or minus for a 1 grain total difference between boolits, thinking that was a fair variance in casting


Now I'm undecided. In handguns cast by someone else I found as much as a 4.4gr. difference in boolits, and in commercial j-word slugs I found a 1.3 and a 2.3 difference in projectiles in the same box.


I was surprised to find that even solid copper commercial slugs ran from .7 to .3 difference in a box.


So, if you are shooting for accuracy in a rifle, how much difference in boolit weight is acceptable?

I'll stick with my plus or minus .5 gr in handgun rounds. (199.5 to 200.5 as an example) Haven't seen anything to tell me that there is much of a difference out to 50 yards using that criteria but am certainly willing to listen to any ideas.

Guess the bottom line is I just have not got good enough at casting to keep the weight of each boolit the same or even close to the same. Some times I have three different groups from one casting session ( 198.5 plus or minus .5, then 199.5 plus or minus .5, then 200.5 plus or minus .5) if that makes sense.

Am I just being too picky and need to lighten up, or is there a real difference in how much the boolit weights when you start reaching past 100 yards?


Can someone educate me as to how much weight difference is acceptable?

[Winger Ed.]

A common thing to do is weigh them out and start groups of which ones are exactly the same.

When you load them, keep them separate and shoot your groups with those of each group on a different target.

And just to see the effects of the different weights being mixed- shoot a group with some light ones and heavy ones.

The difference probably won't be much until you get to longer and longer ranges.
But in competition something small can/will make a big difference.
Example: For some car races, 200 mile, 500 mile, whatever-- sometimes the difference in first
and second place is half a car length when they're going 150 mph or more.

[Springfield]

I never could figure out why some shooters sort bullets by a certain weight, like 1 grain, no matter the caliber. Wouldn't it make more sense to go by percentage of bullet weight? 1 grain makes much less difference in a 500 grain 45-70 than in a 158 grain 38 special, or than in a 55 grain .223.

[dragon813gt]

Weight differences matter more w/ tiny light 22 bullets than a large heavy 45 cal bullet. .1 grain difference is a higher percentage w/ a 55 grain bullet compared to 350 grains.

[Rcmaveric]

Oddly enough, when i took math in college a few years ago I threw all that statistics ** out. Wheb i started reading on hear and actually comparing my reloading and shooting data did I dig all my old notes out. From what I have read abouts here and from my notes in statistics. A 1% deviation from your average mean would be your accuracy zone. Smaller bullets are more affacted and mathematical works out to having a smaller deviation. So if you bullets average 100g then you get a +/- 1g zone and the rest go into the plinking pile if they pass the visual inspection. I do the same with brass uses for accuracy.

In all honesty though, i think grouping brass by head stamp makes or breaks a group. Grouping the brass by weight cuts a group in half. Grouping bullets will only shave a little bit off the group. That one off flyer isnt because you didnt weigh your bullets.

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[jwlegal]

Makes sense to use a percentage of the boolit weight to set some sort of quality control. Thanks
Just curious, am I way off by having boolit's that vary by several grains in one casting session. Seems that once you get started casting good boolits that the weight should be very close to the same. The 4 gr. weight variance I listed in the original post was for a handful of boolits out of a box of 500 that I picked up from an acquaintance at a very good price. They were machine cast and the guy was pretty proud of his alloy mix and how consistent his boolits were. I never thought to weigh them individually until I started tinkering with 150 gr. 30 cal boolits and discovered that they would only stay within 2 to 2.5 gr of each other. Is there just enough change in lead, technique, temperature, all the above plus the phase of the moon to make a steady cast of the same weight unattainable?

[dragon813gt]

If you don’t weigh and plot a bell curve of bullets you make you don’t know how consistent you are. I do this w/ every mold once I have it dialed in. I’m not really concerned w/ pistol bullets beyond how consistent I am. I care about rifle bullets more because I hunt w/ them.

[Land Owner]

NICE visual chart dragon813gt! I weigh each of my cast 22 Bator boolits and have stockpiles segregated by weight (retirement time is what I have, an investigative mind, and I certainly don't mind the tinkering). I get a "bell curve" of boolits (by observation) but had not thought to count them and use Excel to chart the result. I weigh bottle necked cases for rifles too and get a "bell curve" by observation with those too.

I am experimenting (empirically) with the same powder charge to see if it is worth the reloader's time to "normalize" components by putting:
a.) "heavy weight" cases (less powder volume) together with the lightest boolits
b.) "heavy weight" boolits together with the lightest cases, and
c.) "median weight" cases together with "median weight" boolits
to see how those component mixes affect accuracy.

Probably others have done the same, only I have not read their results.

[Lloyd Smale]

don't weight them and then you don't have to worry about it. I don't shoot cast bullet farther then a 100 yards and haven't ever seen it make a difference. At least not one worth worrying about.

[ascast]

dragon813gt nice chart. I have done same or similar many many times for BPCR. Inteteresting that you have a few over weight as compared to those underweight. I always got a similar result, but could never nail down the cause.

[Rcmaveric]

Its normally to see a standard deviation from the mean. I would think 5g is a big deviation. I would expect to see that on my slugdms and 50 cal bullets. Mold temp and alloy temp plays a big part of weight. Thats why it is important to have a good steady and maintainable rhythm. I get my big deviations when I start and then get settled in. And duriing any breaks or pot refills. I normaly start and dont stop till the pot is empty. Keeps my deviations smaller.

Pre heating the mold to the point of the temp you normally cast at will also decrease your deviations. And having a means to consistently cool your mold. I set metronome for temp and use a hot plate to preheat and damp sponge to cool for a 3 count every second cast. Every cast of i am running a high alloy temp because it wants to be a problem alloy.

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[dondiego]

don't weight them and then you don't have to worry about it. I don't shoot cast bullet farther then a 100 yards and haven't ever seen it make a difference. At least not one worth worrying about.

+1 on this, but I do understand that others shoot matches and a few points in score can make a difference in winning or losing. I am just a plinker and a few grains either way won't make or break me having fun. Tin cans and the clay targets that I place on my dirt backstop don't care. I just make sure that the bases are good.

[Lloyd Smale]

99 percent of the handgun shooting competition I did was determined mostly by trigger control I knew guys who could take a cheap 1911 and some steel cased wolf ammo and out shoot 95 percent of the people there. I showed up knowing I had a good gun and knowing by bench rest shooting what the true capability of my load was. Most handgun shooting is at 25 yards or less and ive never seen where weight sorting improved groups at that range unless there was a chunk missing out of the bullet. I would spend my time trying different powders and primers and perfecting my trigger control and spend it more wisely that weight sorting bullets. Now if I was shooting a rifle at 200 yards I might think different. But like was posted even factory jacked bullet unless there match bullets can easily vary as much as your cast bullets in weight and we trust them to kill deer out to 400 yards. A few points or the difference in just missing a scoring line or being on the line can make the difference in winning and loosing. that's a fact and I cant argue. But my guess is if your worrying about things like that causes more misses then the actual problem does. I was told by an old timer once when I started shooting ppc that the first time I met him chewed me out for braging how well my gun did off the bench. He said that the best advice he could give me was to shoot every shot worrying about only that shot and not looking where the last hit and at the end of your shoot turn around and walk away and go and relax and come back in 5 minutes to see your score. Never look at your shot target. He said if you watch your last shot or you mind will take control and you will try to compensate and if you look at your target and see some odd pattern the next time at the line you will try to compensate. Trust your gun and your trigger finger and don't worry about anything else. He said your skill counts for 40 percent, your mental attitude 40 percent and your equipment for 10 percent. I never found a reason to argue with him in the years after. He quit shooting league when he was 78 and died at 82 and was still in the top 10 percent at about every match he went to right to the end. If he could have shot sitting down he probably would have been till a week before he died.

[RED BEAR]

I used to weigh every bullet every case every charge every loaded round until i realized i don't shoot good enough to tell the difference. Now i weigh charges and let the rest sort itself out.

[dragon813gt]

I used to weigh every bullet every case every charge every loaded round until i realized i don't shoot good enough to tell the difference. Now i weigh charges and let the rest sort itself out.

I’m in the same boat. I don’t have enough time to practice w/ handguns. Rifles are the same but I’m not overly concerned. I can’t tell you the last time I shot a deer that wasn’t w/in archery range. I should not be hunting w/ a rifle if I can’t hit the vitals at these ranges.

The reason I weigh and make the charts is to see what my reject rate is. For all but the tiny 22 bullets I want to keep weight variations w/in 1 grain. So +- .5 each way. It’s more about personal pride than anything else.

Here is the second half of the chart I posted earlier. It’s a four cavity mold that’s both PB and GC. It’s one of the things I really like about NOE. The “outside range” percentage is what I care about. I don’t want to throw ten out of 100 back into the pot. Or at least know I should be throwing that many back.



After looking at that, the math is wrong. The outside range total should be higher. Which effects the percentage for that type as well as the overall. I now have to check the formulas and adjust as I save them. Don’t really know why besides I like looking at them every so often

This one is just a random fifty from a large casting session. I’m not going to weigh four hundred plus pistol bullets. There were none outside the range which was a good thing. I’m sure there were some but I didn’t pick them up in the sample.



Someone mentioned above about the run up to the average weight and then a large drop off. This is always the case. I don’t know what causes it. But there’s always less that are heavier than the average.

For all bullets except the ones I use for hunting, I visually cull and that’s it. Bases are the important part. The nose has to have a large imperfection for it to be culled. As long as I can hit the vitals on a man sized target I’m happy.

[T_McD]

....i realized i don't shoot good enough to tell the difference.

This is truth for **** near everyone. I get everybody does things different and that’s OK, but don’t fool yourself into thinking that case prep, boolit weight, etc really matters until you are no longer the weakest link in the equation. For most folks that simply never happens.

[ascast]

When I was shooting a lot of BPCR weighing bullets was standard. It would show at 500 meters. Whether it was from actual cause and effect or just having more confidence in the ammo; I shot better. That was with a 330 grain. I suspect that weighing pistol slugs would be a complete waste of time for all but the most advanced pistol shooters. It would make no difference at all in my pistol shooting.
I like what RED BEAR said.

[Camper64]

dragon813gt, I do the same thing, just let it calculate my means and then min and max range.

[dverna]

I did a study a few years back. My results:

200 gr SWC produced by Dardas on a Magma Caster SD .49 gr Max spread 1.7 gr
230 gr Zero FMJ SD .15 gr Max spread .6 gr
148 DEWC produced by Dardas on Magma Caster SD .64 Max Spread 2.4 gr
148 gr Hornady HBWC SD .11 gr Max Spread .4 gr
130 gr RNFP produced by Precision on Magma Caster SD .89 Max Spread of 3.3 gr.
122 gr TC produced by Dardas on Magma Caster SD .49 Max Spread of 2.2 gr.

The Hornady bullets are swaged thus the consistency.

The 200 gr bullets show a variation of about 1%, while the 122 and 130 gr show just over 2%. But the 130 gr bullets were made by a company that did not have the reputation of Dardas.

My opinion is a 2% variation would be acceptable for most pistol applications except 50 yard Bullseye. That degree of consistency is achievable with cast bullets .35 cal or greater.

After repeated failures., I no longer try to shoot high velocity cast rifle bullets at 100 yards or longer so I am unable to comment on that application. It would seem sensible to conclude that with higher rotational speeds, imbalances caused by weight variation will cause greater groups sizes and as range increases. Others have reported that unlike jacketed bullets that exhibit a relatively linear increase in groups size as range is increased, cast bullet groups expand at a greater rate as range is increased.

[Conditor22]

I've found that unless your shooting competitions or long distance you won't notice a 5% weight difference.

do a test, load 10 with the exact same weight boolit and load 10 with random weight boolits. put them in bags and have someone label the bags A and B not telling you which is which (so your not influenced by the knowledge) and put it in a envelope. after you shot them see how they did