Brass weight... How important?

[DoubleGobble00]

So I've never weighted brass but decided to weigh some today for kicks. The Nosler 300 rum brass varied by 2-3 grains. The ABM 300 WM brass varied about 1 grain. The Lapua 308 brass varied by couple tens of a grain at most.

What is typical? How much does it affect ES and SD? I know it would be best to measure case volume with water but who just weighs brass?

Thanks,

DoubleG

 

[ar10ar15man]

it is all about the little things.
people will tell you it does not mater, they will likely not beat the guy that does.
you are correct volume is better, but most will not do it, so next up is weight.
you decide what matters. simple i like the difference to be as small as possible.
i just sorted some 300 win mag brass new un fired
50 pcs at plus or minus 0.1, 43 pcs at plus 0.3/minus 0.2, 41 pcs at plus or minus 0.3.
that is much closer than most.
the bigger the case the bigger the acceptable variance
i do not understand the nosler 300 rum at 2-3 .it is packaged at 1 per box. i typically buy 2 boxes and resort to get 2 batches at plus or minus 0.5

 

[DoubleGobble00]

Thanks for the info. I'm going to have to start sorting by weight. I did sort yesterday while reloading to see if it helps during load development.

The Nosler brass I'm using was not purchased directly from Nosler. I bought Nosler ammo then saved the brass overtime until I started reloading again. I don't know if that made a difference but the cases did vary 2-3 grains.

I'm curious if the case variations are keeping my ES and SD from getting to single digits. I'm still developing my final load but haven't had single digit numbers yet. On the flip side, I got single digit ES and SD with my 308 (Lapua brass) and 300 WM (ABM brass) with ease.

 

[memtb]

This is just my opinion....I do believe it is important. I see it as much more important on small capacity cases and less important on large capacity.....with qualifiers! It's about % variance of case weight not so much the weight difference in grains. A 10 to 15 grain variance on a small case (say a .223 Rem.) is much more important, that is the same 10 to 15 grain variance on a .338 Lapua case! memtb

 

[Silly_Ghillie]

Oh my, this can of worms is going to explode any day now with endless suppositions and conjectures about case volume versus brass density versus the chemical composition of the shooters toe jam and how long he or she brushes their teeth. With that said, allow me to join the whir. lol.

I typically cull anything outside of 1% of my average grain. if I have enough that falls within the same grain, I will cull anything outside of that weight class. I have seen people use mixed brass and get an SD of 8 and ES of 15. so its hard to say, but for what its worth, I think its a good way to "roughly" determine internal case consistency as far as volume is concerned. I have had good luck with my method so far and I have used it for many years now with some amount of consistency.

 

[ar10ar15man]

while the intend maybe correct the numbers are not.
15 grain diff on a 223..you you actually load match ammo for a 223 ?
they weight 90-100 grains...no such thing as 15 spread by a maker.
my nosler 300 win mag came from the factory at 1 gr spread,, much better that winchester at 5.....but no 10-15's on any make in 300 win mag that i have tested, and i tested a lot.
so yes smaller variation is better.

This is just my opinion....I do believe it is important. I see it as much more important on small capacity cases and less important on large capacity.....with qualifiers! It's about % variance of case weight not so much the weight difference in grains. A 10 to 15 grain variance on a small case (say a .223 Rem.) is much more important, that is the same 10 to 15 grain variance on a .338 Lapua case! memtb

 

[Mikecr]

Capacity matters, weight does not.
You cannot know capacity is matched by case weight (so it isn't).
I could hit each of 10 cases weighing the same with a hammer, and they will each end up at different capacity -while still weighing the same. If I took 10 that weigh the same, anneal them differently and fire-form them,, they will each come to a different capacity.

In no way is weighing cases a shortcut to matching capacities. The only thing weighing is good for is finding problem cases, and that takes a large deviation to know.

 

[memtb]

while the intend maybe correct the numbers are not.
15 grain diff on a 223..you you actually load match ammo for a 223 ?
they weight 90-100 grains...no such thing as 15 spread by a maker.
my nosler 300 win mag came from the factory at 1 gr spread,, much better that winchester at 5.....but no 10-15's on any make in 300 win mag that i have tested, and i tested a lot.
so yes smaller variation is better.

Agreed ......was attempting to suggest that the weight difference on a small case, is much more important than the same weight difference on a much larger case. Not necessarily that you would actually see a 10 to 15 grain difference, on a .223 Rem case.....maybe on a 20 mm AA case! Obviously, I worded it incorrectly! memtb

 

[ar10ar15man]

maybe,
but we do not size them with hammers.
we trim the exterior the best we can with simple tools and size them the same. the alloy in a batch is the same, the density the same, the exterior the same. this tends to provide a uniform interior...volume. in quality brass cases

now i have heard horror stories of extractor groves cut different varying the weight and not the volume. but in my 50 plus years i have never encountered it.never.

and the opposite is true. i have volume checked cases and come up with the SAME volume in cases that WEIGHED the same.

i know mikecr is an accomplished gun person, but we differ on this point.
my experience is different than his.

Capacity matters, weight does not.
You cannot know capacity is matched by case weight (so it isn't).
I could hit each of 10 cases weighing the same with a hammer, and they will each end up at different capacity -while still weighing the same. If I took 10 that weigh the same, anneal them differently and fire-form them,, they will each come to a different capacity.

In no way is weighing cases a shortcut to matching capacities. The only thing weighing is good for is finding problem cases, and that takes a large deviation to know.

 

[entoptics]

Capacity matters, weight does not.
You cannot know capacity is matched by case weight (so it isn't).
I could hit each of 10 cases weighing the same with a hammer, and they will each end up at different capacity -while still weighing the same. If I took 10 that weigh the same, anneal them differently and fire-form them,, they will each come to a different capacity.

In no way is weighing cases a shortcut to matching capacities. The only thing weighing is good for is finding problem cases, and that takes a large deviation to know.

This seems overstated quite a bit, an example of the "appealing to the extreme" fallacy.

If the cases were all run through the same sizing die (or fired in the same chamber), and are trimmed to nearly the same length, then the only dimension that could affect the volume/weight ratio is the the thickness of the case head or rim, since the outside dimensions are essentially identical.

I can tell you for a fact that case weight is proportional to case volume in the above scenario. I weight sorted a huge wad of 223 brass at one point, and loaded an identical charge in the lightest and heaviest. The powder charge was visibly lower in the case in the lightest brass than the heaviest.

 

[aushunter1]

Different case weights means it will affect the case volume due to wall thickness.

Really depends to what degree or how much accuracy you are trying to squeeze out of your loads.
For hunting, Im not really that concerned although I do try to use just one brand of brass & batch them in the number of firings per case.

For benchrest, sure I would be weight sorting cases, & projectiles as well!

 

[jimbires]

I've done this a few times , and could not get brass weight to align with capacity . for me it's check capacity or just shoot it , weighing it is meaningless . I'll look to see if I can find a couple of my weights vs. capacity papers .

 

[jimbires]

here is one

 

[ar10ar15man]

If I took 10 that weigh the same, anneal them differently and fire-form them,, they will each come to a different capacity.

mike i can do the same thing..not hard to do. annealing changes hardness, which means different pressure needed to FULLY fire form. anything less means the harder case will form less and have less volume. it might take several firing to FULLY fire form the hardest.