weighing brass

[guns_and_labs]

I just started weighing my brass, just to see what would happen. I was a bit disappointed that the brass (Winchester) only varied +/- 0.75 grains, with one or two outliers in the bag. I'm not sure that tight a spread is worth weighing/separating, but why not? The summer is long and hot, and my bench is in air conditioned space.

 

[Goofycat]

IMO, weighing brass is a waste of time for hunting reloads. My opinion, from what I have read, is also shared by those far more knowledgeable than I.

 

[AJ Peacock]

IMO, weighing brass is a waste of time for hunting reloads. My opinion, from what I have read, is also shared by those far more knowledgeable than I.

"Hunting Reloads" ??? I weigh the brass on my "Hunting Reloads" I am confident I can be lethal well past 1200yds (Much further in good conditions).

AJ

 

[Moosetracker]

I weight at least 30 once fired cases for each lot of brass I use in order to measure internal volume and enter the average volume represented by grains of H2O in Quickload. I've done this for hundreds of cases of different brands and calibers. Every time I do this I enter the data in an Excel spreadsheet and compare weights and internal volumes. I select the brass on the basis of 1% (+ or - 0.5% from the mean) variation of internal volume. My data shows that the correlation between weight and internal volume is valid less than 50% of the time. With Lapua brass the correlation is valid about 48% of the time. With Winchester brass it's less than 30%.

In my initial sampling of 30 cases, if I find 1 case with a variance of more than + or - 0.5%, I measure the internal volume of all the cases in the lot and weed out those that exceed the tolerance level. In my 338 Edge I've had Remington cases that vary as much as 10 grs and yet had practically the same internal volume. On the other hand I've had cases with similar weight where some where rejected for exceeding the internal volume tolerance.

I weight cases because I have to in order to measure internal volume. However, I'm absolutely convinced that selecting cases on the basis of weight alone is an absolute waste of time. In fact, to the extent that cases are selected by weight that should be rejected for exceeding internal volume tolerances, that practice is a potential source of vertical dispersion in long range shooting.

 

[AJ Peacock]

Moosetracker,

How exactly are you measuring the volume? I've used ball powder and I've used water, I've thought about using Isopropyle alcohol.

What are you doing to the brass after you once fire them, before you weigh and check the volume?

Thanks,
AJ

 

[Goofycat]

"Hunting Reloads" ??? I weigh the brass on my "Hunting Reloads" I am confident I can be lethal well past 1200yds (Much further in good conditions).

AJ

Quote:
Originally Posted by Goofycat View Post
IMO, weighing brass is a waste of time for hunting reloads. My opinion, from what I have read, is also shared by those far more knowledgeable than I.

"Hunting Reloads" ??? I weigh the brass on my "Hunting Reloads" I am confident I can be lethal well past 1200yds (Much further in good conditions).

AJ

 

[Goofycat]

Read Froggy's comments on weighing brass; located below the pic of the loading bench. I don't know the range context he is speaking of, of course. For ultra long-ranges, I would most likely weigh brass and see if it provided better accuracy than non-weighed brass. I don't shoot at 1200 yard ranges, however, so we are comparing apples to oranges. For my shooting purposes, let me say that I don't weigh brass and have had no problems hitting small varmints with reasonably good accuracy.

 

[Moosetracker]

Moosetracker,

How exactly are you measuring the volume? I've used ball powder and I've used water, I've thought about using Isopropyle alcohol.

What are you doing to the brass after you once fire them, before you weigh and check the volume?

Thanks,
AJ

I use water. I have an Acculab Vic 303 electronic scale accurate to .02grs or .001gm. I weight the case and then zero the scale and re-weight with the case full of water. Here's a photo showing internal volume for a Lapua case 6.5x284:

All my cases are trimmed to the same length, deburred, neck turned to the same diameter, primer pockets uniformed and deburred. I measure internal volume with once fired cases without any modifications so as to be the closest possible to the rifle's chamber.

 

[Goofycat]

When you trim your cases to "the same length," do you mean that you trim them to the shortest case in the batch? How much variance from SAAMI case length do you consider a safe deviation from maximum case length, or at least a variance that provides you with good accuracy? I just completed trimming cases and found that the shortest case was .005" shorter than the maximum published length. I haven't been able to get an answer to this question, so if cases are not over the maximum, I just use them, even though their case lengths slightly differ by a few thousandths of an inch. So....should I be trimming to some average case length that is shorter than maximum, or should I find the shortest case and trim all the rest to the shortest case length?

 

[AJ Peacock]

I use water. ...

All my cases are trimmed to the same length, deburred, neck turned to the same diameter, primer pockets uniformed and deburred. I measure internal volume with once fired cases without any modifications so as to be the closest possible to the rifle's chamber.

Sounds like you do it the same way I do. Do you trim after you fire them, or before?

I fire then trim. How do you dry the water?

AJ

 

[Moosetracker]

I do my case prep first and fire after. After 2 firings or so, depending on caliber and/or load, I re-trim all my cases.

After checking internal volume with water, I stand the case upside down on paper towel for a day or 2. Then I resize and de-prime and let the cases dry for another day. If I need the cases sooner, I de-prime and resize then blow dry with compressed air.