Don't bother weighing cases

A&Shuntr said:
Thank-you for your expert opinion on cases, just wish you had of told me about that 35 years ago so I wouldn't have wasted so much time making my benchrest guns shoot through one hole.
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A&Shunter f:P:2:
Correlation does not equal causation... In other words there is probably another reason for your supposed 1-hole groups - rifle, the shooter, the anal reloads. But whatever else it is, it is not weighing brass.
As most of us know (and as knowlegable BigEdP provided evidence to) ballistics have nothing to do with brass weight. People ASSume weight correlates to volume. Perhaps it does with quality brass like Norma or Lapua. I have not checked those, but I doubt it. Have you actually tried to check the volume and see if weight correlates to volume? Those who have actually taken the time know that it does not.

It is simple, but time consuming:
I first neck-sized the brass without decapping it. Ensure same length or trim as needed.
To measure: I removed the powder tray from my RCBS 1010 scale leaving only the hook and tray holder. I then fashioned a shell holder from electrical tape to keep the brass vertical and added weight to compensate for the lack of powder tray. (Electrical tape is non-absorbent in case you miss a drop of water.) Ensure the scales ZERO. Insert a case and weigh it. Then use an eyedropper or pipette as I did to fill the case. Ensure the meniscus is the same, nearly flat surface, for each case.
Then weight it again and subtract. You now have your volume as measured in grains of water. Sort brass accordingly.

Simple right? :)
 
maynard said:
So you think the winners don't weigh their cases? Long gone are the days of issued DA or IVI for fullbore competition when you shot what you were issued at the match.

I was down in Barbados for the West Indies Fullbore Championships last May. Even though is was issued match ammo, the Brits, who won everything weighed and batched every round they fired in the team matches.
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Of course. However, there is a tremendous difference between weighing fully loaded ammo and empty brass. The Brits expectation was to ensure consistency in weight of the powder and projectile. (Perhaps such incidents are where the myth arose). The case weight simply has nothing to do with it. It is the volume that affects ballistics, and there is too many other more significant variables in weight - wall thickness & head thickness.
Case in point: I fire aluminum case, steel case, and brass case ammo. Each case sure would not weigh the same but the trajectory is the same.
 
TheCanAm said:
Case in point: I fire aluminum case, steel case, and brass case ammo. Each case sure would not weigh the same but the trajectory is the same.
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At what distance did you do this testing? Where are you finding aluminum cased and steel cased match ammo?

The ammo used in Barbados was HPS Match ammo loaded down by 1 gr for the heat in the West Indies. Powder I believe was VV N140, loaded into a Lapua case with old style 155 gr SMK's.
I do not think the Brits won the match because they weighed their ammo, they have a very large pool of talented shooters and wind coaches that can be seen in the results from any international match they shoot in. However they do weigh ammo to take every variable out that they can.
 
TheCanAm said:
A&Shunter f:P:2:
Correlation does not equal causation... In other words there is probably another reason for your supposed 1-hole groups - rifle, the shooter, the anal reloads. But whatever else it is, it is not weighing brass.
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I'm glad your knowledge can conclude that there can be only ONE reason for 1-holded groups.
BTW, the RCBS 1010 scale is way to coarse for my needs. I weigh to 1/100th gr. The RCBS unit is only accurate to +/- 1/10 gr.

Bottom line, myself and many, many others will continue to go with what works for us, the proof is in the pudding and is the sum of all effort expended.
 
This is just another example of the typical response to a challenge to shooting "dogma". Facts are irrelevant, it's enough that "everyone's doing it" to shut down discussion. If top shooters started tapping their ammo three times before every shot, soon everyone would be doing that.

I wonder why top shooters don't weigh primers? Their weight should correlate with the amount of primer compound they contain shoudn't it?
 
I do know of a shooter that did weigh his primers. He also weighed all his cases, each powder charge (some of them twice) and each match bullets and batched everything. That year he won the DCRA Grand Agg and the Gov. Gen's Match. Did weighing his primers make him win the match? No, but in his own mind he made the best ammo that he could and it was better than everyone elses because of all the work he did to it.

Now if you want to go to the other end of the spectum, NBRA-Shooter will be along to let us know what he did to his ammo to win his Gov. Gen's match.
 
if your brass is from the same lot, the the density would be the same

different lots = different densities


I have done some reading on this lately as I have some norma brass to process (I'll probably sell off a bunch after)

one article (in accurateshooter?) makes a lot of sense.

one much make each brass identical in outside size, then weigh. that will ensure internal capacities the same. But again, this would only work on same lot brass.

now... I can't shoot near good enough to make a difference for me, but top BR shooters I'm sure do, even if they say they don't
 
This is what I've found . . . . . . .

TheCanAm .........

I've found that it's good to know how consistent your brass weight is. Your case weight variation is not bad at all (especially considering the size of your cases), and you're not exactly dealing with a bench rest caliber. I once encountered some Remington brass that had extreme weight variation. They were Remington 22-250 cases that varied almost 9.0 grains from the lightest to the heaviest. This looked like the ideal situation for testing the effect of sorting cases by weight.

My test rifle was accurate enough to perform a good test that would show the real story. I sorted the my cases into 5 shot groups by weight (not by volume) and fired 20 groups.

RESULTS: The four best groups all had less than one grain weight variation. Two of the very worst groups included cases that weighed on the heavy extreme or the light extreme. All of the other groups were very similar. So . . . . . if you're serious about shooting tight groups, and you have some real crappy brass, it's best to sort them by weight or get better cases.
 
One can get anything from a thread like this that he wants to get, or believe anything he wants to believe.
On the other side of the coin is the real world situations where oft heard theories mean nothing. What happens when we take our rifles out and shoot them?
With this in mind I took five of my lightest 243 cases, which were Winchester, and weighed 168 grains each. I charged these with 46 grains of H414 powder and loaded a 75 grain HP Sierra bullet behind them, and fired them over the chronograph.
I then took five of my heaviest 243 cases, which were Federal and weighed 180 grains each. I charged them with the same charge, 46 grains of H414 powder and loaded a 75 grain Sierra HP bullet behind them and fired them over the chronograph.
Now, according to all the theorists on here who believe in weighing all their cases, the heaviest cases would have less volume, therefore create higher pressure and give the greatest velocity.
The heaviest Federal cases gave an average velocity of 3468 fps.
Of course all the experts know that the lighter Winchester cases would have more volume, therefore give less pressure and create less velocity. The problem was, while the experts knew all this, my ammunition didn't know this and the light Winchester cases gave the greatest velocity at 3491 fps.
 
H4831 said:
One can get anything from a thread like this that he wants to get, or believe anything he wants to believe.
On the other side of the coin is the real world situations where oft heard theories mean nothing. What happens when we take our rifles out and shoot them?
With this in mind I took five of my lightest 243 cases, which were Winchester, and weighed 168 grains each. I charged these with 46 grains of H414 powder and loaded a 75 grain HP Sierra bullet behind them, and fired them over the chronograph.
I then took five of my heaviest 243 cases, which were Federal and weighed 180 grains each. I charged them with the same charge, 46 grains of H414 powder and loaded a 75 grain Sierra HP bullet behind them and fired them over the chronograph.
Now, according to all the theorists on here who believe in weighing all their cases, the heaviest cases would have less volume, therefore create higher pressure and give the greatest velocity.
The heaviest Federal cases gave an average velocity of 3468 fps.
Of course all the experts know that the lighter Winchester cases would have more volume, therefore give less pressure and create less velocity. The problem was, while the experts knew all this, my ammunition didn't know this and the light Winchester cases gave the greatest velocity at 3491 fps.
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well said
 
Weighing cases does not give you internal case volume, all that H4831 proved is there is no relation between case weight and internal volume. Quickload doesn't ask you for case weight, it asks for internal case volume to determine chamber pressure.



Below is the Powley Pocket Computer that came out in the early 1960s and it also asks for case internal volume.



When figuring engine horsepower the weight of your engine block means NOTHING, what does matter is the internal cubic inch displacement and compression ratio.

Does weighing engines tell you what your cubic inch displacement and horsepower is......................NO!

Cartridge case internal volume determines what your chamber pressure is going to be, NOT case weight. And uniformity between cases keeps the internal volume consistent along with your chamber pressure.

99.9% of us in this forum have stock off the shelf factory rifles and weighing cases would do next to nothing to tighten our groups.

Its the people who spend thousands of dollars for custom rifles that benefit the most from tight custom chambers and measuring internal case volume.



I'm 63 years old and have been reloading for over 45 years, I'm retired with nothing to do and all day to do it. I have never put a single drop of water or anything else in a case to figure internal case volume and I don't plan on ever doing it. BUT if I wanted to try and shoot bug hole groups I would buy Lupua brass and not worry about internal volume. ;)
 
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