Weighing boolets

[abunaitoo]

I know this has been discussed before, and seems it really doesn't matter all that much.
But I just had to find out for myself.
I've always thought that if I could get them all about the same weight, consistency would be better.
Friend got me a cheap chinese digital scale.
I weighed a bunch of 309/160gr.
Never got close to 160gr.
Varied from 151gr to 155gr.
I sorted it down to closest to 154gr.
I'll see how they shoot tomorrow.

[sw282]

l shoot IHMSA Silhouettes. A 200meter game for handguns.. Lots of shooters cast their own boolits in pistol/rifle calibers from 22Hornet to 45Colt.. These guys usually weigh/sort their boolits down to 'tenth of a grain'..

[high standard 40]

I also shoot IHMSA and I weigh my bullets. When I started down the path of casting for competition I tried to remove as many variables as possible because I have no access to a place to test my loads or practice. My 7mm bullets are sorted to +/- one tenth grain. To answer the question of does it matter, I can't really say because I've never done a side by side comparison. But my system works very well for me so I'll stay with it. I've heard it said, and I can't argue the point, that you don't need moa accuracy to hit a full size silhouette ram. But if you get in a shoot-off, the targets can get as small as 4-6 inches at 200 meters. At that point, I want all the accuracy I can get.

[Larry Gibson]

"I weighed a bunch of 309/160gr.
Never got close to 160gr.
Varied from 151gr to 155gr"

The nominal weight of the bullet is with the alloy the mould was cut for and with the bullet "fully dressed" [GC'd and lubed]. If you were using another alloy then the weight will be different. The GC & lube will add 3 - 4 gr +/- on a 30 cal bullet depending on type of GC and lube/amount used.

"Friend got me a cheap chinese digital scale."

Perhaps some of the problem is there...........

[ascast]

abunaitoo it is worth a mention- electronic scales will drift with a temperature. It does appear that this happened to you, but it can. You need to be aware and watch for it.

[mwells72774]

Another thing about digital scales, make sure they have a warm-up period

[Rcmaveric]

Weighing sorting bullets didnt really show a difference for me out to 200 yards.

Sent from my SM-G950U using Tapatalk

[Petrol & Powder]

I've weighed rifle bullets and culled the ones that were on the heavy and light ends of the mean. It gets very tedious if you want that spread in the center to be within 1 or 2 tenths of a grain. I'm not a benchrest shooter but those guys know all of the tricks to making consistent cartridges and you can learn a lot from them.
There IS a payoff in consistency by weighing bullets, therefore accuracy to be gained, but I'm not sure where the diminishing returns overcome the benefits.

An electronic scale is useful to start the sorting process but you really need to switch to a mechanical beam scale to finish the weighing process. The electronic scale is used to cull out the bullets that are grossly heavy/light compared to the rest but when you get down to 1 or 2 tenths of a grain, it's easier to switch over to a mechanical scale for the last cull.

[Land Owner]

Chinese scale? Which one...they are all built in China but some are "less" than others.

If it is one of the YELLOW plastic bodied scales, it is worth what YOU paid for it, and I would not trust it.

If it is another color, then check it periodically with a KNOWN weight, and plug it in at least 5 minutes before you use it.

I trust Larry Gibson in post #4 above.

[JonB_in_Glencoe]

Another thing about digital scales, make sure they have a warm-up period

Yep.

I have a Cabela's digital scale, it wasn't cheap and it's been real good to me over the years, but there are two things I've learned about it.
>Warm-up period is a couple minutes. Turn it on, wait a couple minutes and then Zero it.

>a ceiling fan(even set low) or a breeze from an open window can effect the measurement by about ±1.0 gr.

[lightman]

I've weighed a lot of my bullets over the years. I've found that most of them are as close in weight as the medium priced J-Words. Occasionally I will find one thats off a couple of grains but not often. Usually theres a flaw thats visible but not always. If you're shooting a man sized target at 21 ft I'm not sure that it matters. If you're competing at 100 or 200 yards or more, yeah it probably does matter. Weigh several and see what you get. Then shoot a few groups with the keepers and compare it to a group shot with the rejects.

[Larry Gibson]

For weight sorting to be beneficial it must be done properly. Also you must be casting quality bullets. If, when weight sorted, you end up with a "bell curve" of weights and eliminate the heavy and lightest bullets for a +/- in the middle of the "curve" then your efforts will probably not be beneficial as many find out.

If you are casting high quality bullets for accuracy, especially at HV, at longer than 100 yard ranges then the proper technique of casting must be done to see benefit from weight sorting. If you are casting quality uniform bullets then you will not end up with a "bell curve" of weights but will instead have an ascending curve to a plateau of weight and then a drop to only a very few "heavy bullets" out of several hundred cast.

Here's a graph demonstrating such a plateau curve based on 500+ bullets weight sorted. I ended up with 350+ "match/HV" quality bullets.

238976

Here is a further explanation in response to a post on another forum;

"For your theory, that lighter bullets in a batch are less accurate than the heavier ones we must assume: 1. that light bullets are caused by voids, 2. that those voids are not too near the longitudinal axis and, 3. that they are large enough to be significant."

Ergo is the problem in this discussion. I do not subscribe to any of those 3 assumptions. In fact if you re-read my post with the graph I explain what I've found to be the real problem and it is not the suspected or assumed "voids" in the bullets. Yes, that's what we've all been told for probably a hundred years and it is what we've based our testing on.

Ten years ago I thought I was casting pretty good bullets, excellent in fact. However. the more I got into shooting cast bullets at HV I found while I was casting good, excellent bullets I too hit the accuracy wall that joeb is alluding to. I also found that when those cast bullets were pushed to really HV (2500 - 3000+ fps) they did not do as well as expected. Back then I was weight sorting as we've all been told to. If you line them out by weight you get the so called "bell curve". In proving insanity I, like you and everyone else, then did the same testing of each .1 gr testing over and over again expecting different results.....we all got the same results; accuracy was not really improved via that method no matter how many times we ran the test. You are asking me now to run the same test and think I will come up with different results? It wouldn't happen.

Let's assume we have a mould that will cast perfectly even bullets in all dimensions. Not an assumption but fact is that mould has a finite capacity for any alloy. Thus if we cast with a good alloy giving the best fillout then only those that weigh the heaviest will have filled the mould out completely. Any bullets with less weight are then not dimensionally the same. We may not be able to measure other than weighing that difference but the difference is there in lighter weight bullets none the less. Now that difference in weight (mass) is there but it is not predictable.....we don't know where in or on the bullet that difference in weight is missing from. The missing weight is what creates the imbalance. I suspect voids in the alloy are not the problem but rather other aspects are which I have previously discussed.
I recently cast 542 NOE 30 XCB bullets of #2 alloy. I have just completed weight sorting them. In the next post I will show the graphed results of the weight sort which should aptly demonstrate what I'm saying. Have to copy, download, etc. so it will be an hour or so.

Here is the results of the weight sort. 542 bullets were cast of Lyman #2 alloy and WQ'd. They were then aged about 12 days before I got around to weight sorting. Here is my set up for weight sorting. I visually inspect each bullet for any defect. If any is found that bullet is rejected to be melted and recast at a later casting session. Those that pass my anal visual inspection then have any remnant of the sprue cut off. That is done on the lead block with a sharp blade on the pocket knife. The bullet is then weighed on the Redding balance beam scale. While waiting for the beam to settle I then visually examine and sprue cut another bullet. With the magnifier in front of the scale I can readily and accurately see what the weighed bullets exact weight is. The bullet is then placed in a bin for that weight.

Of the 542 bullets weighed 22 were rejected for a visual defect or because they weighed less than 156.9 gr which means the weighed ones had passed the visual inspection but still weighed way lite. The remaining 520 XCBs were weight sorted into separate bins of .1 gr increment from 156.9 gr to 158.0 gr......a 1.1 gr spread.

Here is the rough graph of the weight sort. As you can see there is no "bell curve". The curve rises from 156.9 gr slowly to 157.5 gr and then rises sharply. The "curve" then plateaus out at 157.7, 157.8 and 157.9 gr with 113, 124 and 110 bullets for each weight. The "curve" then falls sharply to just 9 bullets at 158.0 gr. Of those 9 bullets only 2 actually weighed 158.0 gr. The remaining 7 bullets weighed between 157.9 and 188.0 gr. There were no bullets heavier than 158.0 gr. (graph posted above)

The weight sorting is showing us the 113 bullets of 157.7 gr, the 124 bullets of 157.8 gr and the 119 bullets (I'll put the 158.0 gr bullets in with those) of 159.9 gr weight has the highest weight/mass of alloy in them. Since the curve dropped off suddenly we see those weight bullets are the most consistent and the best the mould will produce with that alloy. Those 356 weight selected bullets will be used for best accuracy.

The 157.6 gr bullets will be used as fouler/sighters as I expect they will give very good accuracy also given only a .2 gr +/- difference in weight.

Had we lumped all the visually selected bullets into one group 70% would have been with the excellent bullets, another 15% would have been with the fouler/sighter bullets and the remaining 15% would have been with bullets having a weight/mass difference of 1.1 gr. Now, had I done that I probably would have got nice 1 1/2 moa groups with 7 +/- shots going into moa or less and 2 -3 +/- shots going out of the group in the 1 1/2 moa +/-. How many of you shoot groups like that with bullets only visually sorted?
It is with such weight sorted selected bullets (the 157.7 to 157.9 gr bullets) that I am able to hold moa accuracy to 300 yards and beyond with a 2900+ fps velocity.

Here is the result of testing at 300 yards with 10 shot groups.

238977

Those are some nice groups. With regard to consistent boolit weight, what do you consider consistent? Plus or minus X.X grains?
It depends on the weight of the cast bullet to begin with. Most weight sort thinking those bullets that weigh the same or with a +/- will shoot the best. I've learned that while that method of selection will give better accuracy it will not give "the best". As I weigh each bullet I visually inspect the bullets first. Any visual defect, no matter how small, is cause for rejection. I then weight sort to eliminate those very light bullets that passed the visual inspection but obviously have a void inside. I then put the bullets into small plastic bowls of .1 gr increments.

I'll explain with 7mm to 32 caliber bullets of 150 to 220 gr as an example. Many who weight sort will kind of "graph" the bullets out by lining them up in tenth grain increments that are consecutively numbered and straight across the bottom. What you end up with is a "bell curve" shape of bullets. The curve starts out curving up, peaks out and then curves back down almost the same as it went up. The majority of the bullets in the curve will have a 1 to 1.5 grain difference in weight. There will be some that are much lighter and a few heavier. That is what you get with "good" cast bullets.

Using a quality alloy that will cast excellent bullets is also paramount. This is why straight linotype and #2 alloy are most often used. They give excellent and uniform fill out, consistency of weight with fewer defects. Some batches of COWWs will also if the antimony and tin percentages are sufficient and balanced. Alloys in these smaller caliber bullets that give a lot of shrinkage will never cast "excellent" bullets no matter how good they look. The reason is we cannot control the shrinkage and where it occurs on each bullet. Slight shrinkages that are in different places on the bullet are undetectable by visual or even precise measurement and they mean a slightly unbalanced bullet. Might not seem like much but at higher RPM and/or at longer ranges of 200 yards and beyond it is readily detectable on target by enlarged groups and poorer accuracy. Complete fill out in the mould and minimal shrinkage is needed for a quality cast bullet that will give the best accuracy.

Weight sorting the visual inspection passed bullets with "excellent cast" bullets gives a weight sorted curve that rises sharply and then levels off with several weights (three or four of .1 grain increment) having about the same number of bullets. The curve then falls sharply to just a few heavier bullets. There is no downward "curve".

When I got the 4 cavity NOE 30 XCB mould I ran this test with Lyman #2 alloy;

I cast 531 bullets

1.9% were rejected for visual defects

8.6% weighed less than 157.7 gr (some as much as 2 gr less that obviously had internal voids I could not detect through visual inspection)

3% weighed 157.8 gr

4.5% weighed 157.9 gr

5.9% weighed 158 gr

18.7% weighed 158.1 gr

19.3% weighed 158.2 gr

21.6% weighed 158.3 gr

14.7% weighed 158.4 gr

1.8% weighed 158.5 gr.

I then loaded 10 shots of each increment (157.8 gr to 158.5 gr) to test at 300 yards.

Test rifle was my 30x60 XCB. The NOE bullets weight 164 gr +/- when fully dressed and were loaded over 53 gr of AA4350 which runs 2900+ fps out of that rifle. The incremental test loads were fired consecutive by weight with the barrel cooled, cleaned and then fouled with 2 fouling shots prior to the next increment test. The results were then graphed out for a simple visual comparison.

We see the lighter weight 157.8 and 157.9 gr bullets were not as accurate. The lighter weight bullets giving indication to probable incomplete and inconsistent fill out and/or shrinkage or that they have small void(s) in them. The "heavy" end of the bullets (158.0 through 158.5 gr) gave consistent accuracy (precision) at very close to moa at 300 yards. I have run this test several times and with cast bullets in the 150 - 180 gr weight range I select the heavy end of the weight sorted bullets +/- .2 to .25 gr. With this weight range I use the 157.8 and 157.9 gr bullets for foulers and the 158.0158.1 bullets for sighters. The 158.2 through 158.5 are then used in matches and other tests where precision is measured. For the best accuracy at this level of high velocity the top half (158.3 to 158.5 gr) of those selected bullets almost always give the best results, particularly at 200 and 300 yards.

With other weight ranges I like wise run a similar weight sort test and now select the heavy end of the match selected weight sorted bullets for accuracy/precision use.


That is how I weight sort and why it makes a difference.

[koger]

I shot ML's in competition on a local, state and national level for several years. I weighed all my round balls two within 2/10ths of a grain, plus or minus. I did see accuracy increase, even in my offhand competition. When shooting cross sticks or prone, at 50-60yds, my groups would be a ragged hole for 5-10 shots, whichever the match called for, the hole would be about the size of 3 bullet holes, all partially overlapping. The big difference when weighing bullets, would be the one which had a air pocket and was way light, and when cutting them open, would find the voids all over the place. I shot several of them benched at 50 yds, and instead of a ragged hole, would often times have a group 3-4". Imagine shooting a good score, and got down to your last bullet, and it went outside the group about 2-3". I have seen that happen with good shooters and guns, who laughed at me and a buddy for weighing bullets, developing a really consistent patch lube that shot the same all year long. One day as one of them was hacking on me, we looked up the last 5 matches we had shot in, 2 targets at 25 and 2 at 50 yds, and my buddy and I were beating the other guys between 15-20 points total. That got them scratching their heads, asking about our patch lube, and all of them started weighing their balls after that!

[high standard 40]

One positive thing that weight sorting has done for me is that it was a tool for me to cast better bullets. When I found wide weights in a batch of bullets, it showed me that I needed to change techniques with that mold and alloy. I kept adjusting techniques till I got consistent weights. In this manner, weighing made me a better caster, which in time made weighing less important because I was making better bullets.

[Petrol & Powder]

So allow me to add that when I spoke about weighing rifle bullets and culling out the light and heavy bullets (the ends of the bell curve), I was speaking about commercially produced jacketed bullets. If you are dealing with cast bullets, you are far more likely to be dealing with voids in the bullets than when dealing with cores swaged into jackets.
I agree with Larry Gibson's statement that you do not want to seek out the center of the bell curve when sorting cast bullets by weight. In that situation you do want the heavy end of the spread (or the heavy side of the curve if plotted on a graph).

However, when sorting commercially produced jacketed bullets the goal is to collect a group of bullets that are as close in weigh as possible. You will simply have more bullets in the middle of that bell curve than on the ends of that curve. The differences there are not voids but rather slight differences in the length of the cores and thickness of the jackets.

[Echo]

Super thread...

[abunaitoo]

Well I tried it.
Range is only 100yd so I don't think it a fair test.
From 1.0ge to 3.0gr difference, it didn't show any accuracy variation.
Probably make a difference at 200yds, but we don't have a range that long.