Weighing bullets

Discussions of powders, bullets and loading information.

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rgchristensen
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Weighing bullets

Post by rgchristensen » Wed Feb 20, 2019 10:29 pm

When I started seriously playing this game, ca 25 years ago, I was an inveterate weigher-of-bullets. What all the weighing of bullets taught me is HOW to cast bullets, and I now think that is the only reason to weigh bullets, to check on your casting skill. Another lesson is not that the bullets must weigh the same, but that they should be perfect. If two bullets, cast of the same alloy in the same mould, vary in weight, at least ONE of them has an imperfection in it. Many times these can be observed by cutting into the bullets. Pick a "light" bullet and grab it horizontally in a vise just below center. Shave off lead with something like a sharp wood chisel, and probably when you get near the center of the bullet, you will find a cavity, perhaps 0.040 - 0.050" in diameter and up to 1/4" long. Lead being soft, when the bullet is fired, the cavity will collapse, and the possibility arises that the bullet will become unbalanced. Or maybe not, because the shrinkage cavities tend to be near the center-line of the bullets.
Now to the experiment.... I collected maybe 50-odd bullets, including a few judged to be of "perfect" weight, and many varying up to 5-6 grains less. The weights were written on the ogives of the bullets and they were loaded into cartridges. These were fired, scope/bench, at a target consisting of a grid of lines, so that each bullet could be fired when aiming at a different grid intersection for each round. This allowed the calculation of the mean point of impact of all the bullets, each with respect to its own grid intersection, and then the variation of the point of impact of each bullet from the mean point of impact. The variation of each bullet from the mean POI was plotted vs. the weights of the bullets, expecting to find a general trend of wider dispersion of bullets of lighter weights. Surprisingly, this did NOT occur. Most of the bullets were distributed close to the mean point of impact, but the occasional ones which were noticeably outside the usual distribution ("3-sigma fliers" if you will) became more frequent. These fliers amounted to about 20% of all the bullets tested. BUT remember that these were, for the most part, bullets that would have been rejected by weighing, and were perhaps only 5% of the bullets cast. 5% of 20% is only 1%. My conclusion was that weighing bullets, therefore, was not worth the trouble.
I hope that this will be of interest. Many will likely not agree with my conclusions -- maybe it will lead to a good discussion.

CHRIS
RGChristensen

bruce m
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Re: Weighing bullets

Post by bruce m » Thu Feb 21, 2019 12:18 am

good post chris.
thanks for sharing the experiment.
bruce.
ventum est amicus meus

Woody
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Re: Weighing bullets

Post by Woody » Thu Feb 21, 2019 3:30 am

and I now think that is the only reason to weigh bullets, to check on your casting skill.
I totally agree. I quit weighting many years ago. Now If I could only bring myself to trust my observations on weighing powder charges.

Woody
Richard A. Wood
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BFD
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Re: Weighing bullets

Post by BFD » Thu Feb 21, 2019 6:32 am

I hope more people stop weighing bullets.

I recommend it for all competitors (except me).... :)

SchuetzenDave
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Re: Weighing bullets

Post by SchuetzenDave » Thu Feb 21, 2019 8:16 am

Agreed.

Match grade bullets are considered to be within 1% total variation.
So for a 500 grain bullet: all bullets within 5 grains variation is match grade and will have no influence on accuracy.

In the Schuetzen game I shot a 1,245 out of 1,250 points (@200 yards 45 bullseyes and 5 bullets slightly over halfway outside the bullseye ring).
They were bullets that were never weighed.

However I only shoot bullets with sharp square bases.

Rounded bullet bases will affect accuracy.

Yes I precisely weigh all powder charges.
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Don McDowell
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Re: Weighing bullets

Post by Don McDowell » Thu Feb 21, 2019 8:25 am

I think it depends a lot on what you're going to do with those bullets.
Handgun bullets and other applications where the use will be short range I doubt it matters much. I seldom weight those except just to see what they do weigh with a given alloy.
Silhouette, yes I would imagine that after the mould is warmed up and things are humming along nicely a person could get by well enough to not bother weighing, so long as the bases are all looking good.
Long Range, anything beyond 500 yards, I think the extra attention to detail pays off. Weighing not only gives you a second chance to observe any obvious defects in the bullets, it also gives a bit of mental confidence knowing the uniformity of the bullets won't be causing you grief.
2 shots in the 6 ring , where the second shot takes out the spotting disc will beat an X and a miss every time. :wink:
AKA Donny Ray Rockslinger :?

rgchristensen
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Re: Weighing bullets

Post by rgchristensen » Thu Feb 21, 2019 9:22 am

I certainly agree that confidence in the performance of ones' equipment is an important factor. If it makes you feel good, do it!!

CHRIS
RGChristensen

BFD
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Re: Weighing bullets

Post by BFD » Thu Feb 21, 2019 9:32 am

I'm not as good at casting as everyone on the forums. I cast 100 bullets or so at a time. Prewarm my mould on a hot plate. Toss back the first few bullets just to be sure.

But I still weigh my bullets. And I still continue to find 2 or 3 bullets that are as much as 1 or 2 grains off the "norm". while the rest will fall within a 1/2 grn of the mean and mode for the session. They look good too. Might even shoot into the center. But they might also be one those "in the window" shots on rams or, god forbid, pigs. Happens. I've seen it.

I would never, ever make a decision to weigh or not weigh on a target like SchuetzenDave's. As nice as that target is. It is just a target and only at chicken distances.

Kurt
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Re: Weighing bullets

Post by Kurt » Thu Feb 21, 2019 10:05 am

I used to weigh my bullets also but quit. I used to cast with a loose plate that would swing freely and I used to get a lot of variances in weight. I split several the light bullets to see if they had voids but I never saw a clean hole I always saw dross that got into the cavity. This started me to take a rag with lube on it and I rub it on the ladle spigot so the dross don't stick on it and this stopped it. Also most of the weight variances come from the loose sprue plate getting pushed up or held down. When I cast the spigot is tight on the plate with the hole on the side and when I turn the mould and it's upright I lift the ladle off the plate and let the alloy empty over the hole making the vibration it creates fill the cavity, but what I found doing this with a loose plate was it raised the plate and this added some weight so my plates are tight and I need to push the plate with a wood dowel I use to cut the sprue and move the plate and the base edges are sharp.
If a bullet drops more then 5/10 light from the heaviest I changed something in my pour mostly stopping the pour too soon.
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Mustang1
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Re: Weighing bullets

Post by Mustang1 » Thu Feb 21, 2019 11:30 am

I am NOT as good a caster as those on here but I weigh all my bullets and segregate plus or minus 1/2 grain.

LazyM
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Re: Weighing bullets

Post by LazyM » Fri Feb 22, 2019 2:30 pm

Wish I was someone from the "upper tier" that really know these things... however, here is my 2 cents.

I try to cast as much as I can in one day. The reason? The casting, and the weights, are more consistent. Interestingly, I have noted that bullets cast the next day will have the same weight distribution, but perhaps + or - half grain. Not really any different, but I noticed it.

Having said the above, I weigh and group my cast bullets by .1 grain. Yes, .1! And having said that, all I think that really does is give me confidence in the cast bullets. Any deviation on the target is surely that of the shooter, nit the gear.

Do what makes you comfortable. It can only give you confidence in that area. Then move on to the next "problem" area of this sport! 😁🙄

Kurt
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Re: Weighing bullets

Post by Kurt » Fri Feb 22, 2019 3:18 pm

Weighing bullets is a :D
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The reason a dog has so many friends is because he wags his tail instead of his tongue.

"Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery Winston Churchill

Glen Ring
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Re: Weighing bullets

Post by Glen Ring » Sat Feb 23, 2019 6:29 pm

I have only been shooting BPCR 2 years so I'm no expert. I weigh all my bullets to the grain and that's how I shoot them...in groups of 535 grain, groups of 534 grain..etc.
I pan lube in the oven on low heat with spg lube. When the lube has melted I turn off the heat and wait for the lube to solidify..then I place the pan in the freezer for a few minutes.

I push all bullets out of the block by pushing on the nose..especially the bullets with different diameter bands. I push another batch of weighed bullets in the holes and then start all over.
I weigh all powder charges and make sure all bullets are seated in one setting.

How many folks use a flash hole uniformer on their cases? I enjoyed the advice and help offered by Brain Chilson last year at my fiirst nationals in BPCR, but I don't know his handle on here to ask him specifically.

Everything Brian told me helped a lot.
All hail Don, the stirrer of the pot , writer of self-promoting Novellas and decliner of challenges.

BFD
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Re: Weighing bullets

Post by BFD » Sat Feb 23, 2019 6:35 pm

Glen, I think you have a good system going. (of course I don't use grease grooves). Stick with it.

I think flashhole uniforming is unnecessary, at least for Starline brass. They are very consistently made and I have seen no advantage to messing with them.

I do not believe Brian posts on this forum. Could be wrong but I've never known him to be a poster here.

Brent

SchuetzenDave
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Re: Weighing bullets

Post by SchuetzenDave » Sat Feb 23, 2019 8:21 pm

I uniform both the primer pocket as well as the flash hole on all brass I shoot competitively.
A uniform primer pocket results in the exact same firing pin ignition with equal distances to every primer fired.
The flash hole may not be perfectly circular and may have a drill burr splitting the ignition flame.
Uniforming it results in a consistent ignition flame.

Starline brass is very good and not much is removed.

Winchester brass is the worst and uniforming it greatly improves the consistency of ignition.

Target above was shot with uniformed Remington brass.

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