Mikecr
Well-Known Member
Thickness, and thickness variance.
Same thickness in lot = consistent response to the load
Low thickness variance = straighter sized cases
How much do you value brass brand consistency when reloading?
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Same thickness in lot = consistent response to the load
Low thickness variance = straighter sized cases
MagnumManiac
Well-Known Member
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- Feb 25, 2008
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I shoot F-class and 2K comps, and I haven't weighed a single piece of brass in a very long time…
Brass weight, compared in grains of water, means very little, sure, it tells you how much the water weighs, but it doesn't tell you the whole story if you take that number from a random piece and then extrapolate that number to every other piece. As @Mikecr alluded to, it doesn't tell you WHERE differences may lie…
Not all forming/drawing is identical, the slug/cup the brass is formed from may all weigh the same, but if the draw causes thickness variation ANYWHERE in that case, volume is changed.
I measure volume in CC's, weight to me means nothing, of 20 random cases in a 100 lot batch, but I generally buy bulk lots of brass. 500-1000 depending on what's on offer at the time. I bought 5000 222Rem cases at one time, haven't even used 10% of them yet.
This measurement after ALL prep, neck turning, neck sizing to MY parameters, trimming and flash hole demurring tells me what is consistent and what isn't.
Never assume weight similarity means volume is the same.
I have Remington and Winchester brass from 20 years ago that weigh very similar, discovered when I weighed brass, and the volume is very different, sectioning a piece of each showed Remington internal structure very different to Winchester. Winchester has a thick web of .045", walls are tapered from a thick section near the web to thinner going up the case, Remington has a .030" thick web, heavy walls going straight up from the web and staying thicker for about 70% of the body. The Remington case has less volume, which is why loads from the Winchester cases are over pressure in the Remington brass…
Cheers.
Brass weight, compared in grains of water, means very little, sure, it tells you how much the water weighs, but it doesn't tell you the whole story if you take that number from a random piece and then extrapolate that number to every other piece. As @Mikecr alluded to, it doesn't tell you WHERE differences may lie…
Not all forming/drawing is identical, the slug/cup the brass is formed from may all weigh the same, but if the draw causes thickness variation ANYWHERE in that case, volume is changed.
I measure volume in CC's, weight to me means nothing, of 20 random cases in a 100 lot batch, but I generally buy bulk lots of brass. 500-1000 depending on what's on offer at the time. I bought 5000 222Rem cases at one time, haven't even used 10% of them yet.
This measurement after ALL prep, neck turning, neck sizing to MY parameters, trimming and flash hole demurring tells me what is consistent and what isn't.
Never assume weight similarity means volume is the same.
I have Remington and Winchester brass from 20 years ago that weigh very similar, discovered when I weighed brass, and the volume is very different, sectioning a piece of each showed Remington internal structure very different to Winchester. Winchester has a thick web of .045", walls are tapered from a thick section near the web to thinner going up the case, Remington has a .030" thick web, heavy walls going straight up from the web and staying thicker for about 70% of the body. The Remington case has less volume, which is why loads from the Winchester cases are over pressure in the Remington brass…
Cheers.
FireFlyFishing
Well-Known Member
As I concluded…something to worry about when I'm retired.
Mike Matteson
Well-Known Member
You got that right!
Barrelnut
Well-Known Member
^^^ THIS ^^^
Different brand cases have different internal volumes. This has to be taken into accound. Depending on the difference, it can even get boardline dangerous sometimes.
Mike Matteson
Well-Known Member
You save me a bunch of writting!
That completes this story. Theirs a lot to working up brass to start with. I sure as hell wouldn't mix head stamps. Back in the days.I weight my brass. Found from different head stamp the case varied over 30grs. I use volume weight now. I also work my case over before checking the weight. I cut all cases to length, cut the necks to a thickness, check primer pockets and flash holes. This is with new never been fire cases.Using mixed head stamp brass is dangers, especially with different powder loads and at max. Temp Sensitive Powders change your velocity by as much as 1.5+fps per degree. That changest the chamber pressure at the same time. BEWARE!
I used to measure neck thickness but never saw a large enough variation to do anything about so I stopped.
If you had a large enough thickness variation it may cause inconsistency but i've never personally seen it within one lot of brass
Mikecr
Well-Known Member
I've seen it. Thickness variance as measured at necks runs full length of the case.
That springs back differently leading to high runout. Once you've run out of loaded chamber clearance (if you do) that runout causes random chambered pressure points, that can throw shots.
I run tight clearances & minimal sizing, so I need straight cases.
But sorting by thickness variance, running tight clearances, and minimal sizing, happens to produce ultra straight cases (<1thou TIR off exposed bullet bearing). Problem solved.
I suppose most people don't actually need low thickness variance like I do. I'm just throwing it out there as that's what I do.
The bigger matter is thickness itself.
If you measure 12thou at a neck where most cases are 13thou, that issue likely presents elsewhere down the case.
This, affecting case response to pressure.
I keep only cases within 1/2thou of thickness in a batch, and THEN I turn necks (if part of my plan).
The purpose of matching case capacities is to reach consistent case response to pressure.
But capacity is not the only attribute affecting this.
Case hardness and chamber clearances are bigger than capacity itself.
If I could. Id go back to when I began reloading and give myself a piece of advice it would be this. Buy a Forster shoulder bump neck sizing die for every different cartridge you load.This isn't for straight wall cases. I have over forty sets of dies. Actually, more then that, that I have bought over the many decades I've been loading. You will get perfect neck tension each time you use it,and have perfect chamber fit for your case. The brass will last a very long time. And you won't end up like me with a box of old dies I never use anymore. Remember this when loading, if you say this thing is not like the others, don't do it.
memtb
Well-Known Member
Rosebud, the "wow" 
emoji just doesn't do justice to the number of reloading dies you have……combine this with the apparent number of Forster shoulder bump/neck sizing dies.
I bow
in admiration to you sir! memtb
emoji just doesn't do justice to the number of reloading dies you have……combine this with the apparent number of Forster shoulder bump/neck sizing dies. I bow
in admiration to you sir! memtb
I only have five of the forster, for what that's worth. About half of the other dies I acquired from other people I loaded for. Their stuff. My knowledge. They never came back to reclaim them.I've over a dozen of calibers I've never owned. I need to have a yard sale. I also have Herters pistol,30-30 and 303 dies. I still use the herters sizing die.Rosebud, the "wow"
I bow
NC Varmint Shooter
Member
I agree with all the members above use the same brand brass if you want to get the same pressure and accuracy from each round. All Brands of Brass have different walI and web thickness this will build higher or lower pressures when the round is fired. If you want good brass at a reasonable price, try Starline Brass. I was using Lapua and Nosler till a friend told me to try the Starline brass in my 260 Remington and 6.5 Creedmoor. I'm getting 4 to 5 firings from each case and the Primer pockets are still thigh, with annealing the brass I could get more firings. You can go straight to Starline Brass web site and buy brass from them at a reasonable price.
