Case capacity by brand can vary by 8 Graines!!!

[Stats Shooter]

I have posted several bits of mostly useless info on this forum in the last couple weeks but here is something that is useful to everyone. All the experienced guys know this fact, and folks who do not know it but follow good safe fundamental handloading practices won't be adversely affected. However the ignorant (like me) and reckless (not me) could have a serious issue.

We all know that a cardinal rule of handloading is to use manuals, software, and online load data as a guide, but the load must be worked up in your rifle. Then, another rule is that you must re-work any load if you change a component such as powder, bullet, primer and brass...Or if you change the jump, and anything else I'm leaving out.

But since I have gotten Quickload I am shocked to find out some information about a cartridge I have been loading for years. The .300 win mag.

First, let me state that SAAMI volume of water in a .300 wm is 92.2 gr. In my old .300 wm hunting rifle I used to use RP brass and always had to stop well short of published max loads because I was seeing pressure signs. I also couldn't get velocities as high as the book said,or even close. Well, RP brass has a case capacity of 88.5 gr water....3 less than SAAMI.

Later on, as I have gained more experience I began checking case capacity but never did a comparison, and I never checked the Remington brass I used before which is long gone now.

I now use Norma brass in .300 wm and if Remington is a studio apartment, Norma is a mansion. Norma holds 95.5 gr water as per QL. I checked several of my own cases and found an average of 95.4.

That is an 8 grain difference in Volume!!! You see countless load recepies on the internet where people are meticulous about their jump, powder, primer etc and gloss over the case part. But this should illustrate, at least in some cartridges, how important it is.

Just a quick example, my load I have settled on is 79 gr H1000, around 2900-2910 fps. 58,204 psi. MAP is 64k

In a Remington case,all else equal, that load would hit 78,153 psi and 3031 fps.... Not good.

As I said, not knowing the pressures isn't that important, provided you rework your loads when changing components and back off when things tell you too. But this illustrates just how important that rule is. While other cartridges may not have such extreme differences like the .300 wm, even a 2-3% difference in capacity can have a dangerous difference in pressure.

Hopefully someone new to hand loading will read this and avoid a catastrophic mistake.

[Metal god]

Haha lol 8gr ain't nothing . There are 308 cases that have a 30+ grain difference . I have some RWS cases that weigh in the 190gr area and i believe there e are some 1970's winchester cases in the 156gr area . I have some winchester cases now in the 175gr area and all my LC cases are in charge he 185gr area . Welcome to the wonderful full world of reloading

[disseminator]

I have seen 4-6g difference for my 7mmRM, it definitely is very important to reduce and rework if you change your brass.

[Stats Shooter]

Haha lol 8gr ain't nothing .......
winchester cases in the 156gr area . I have some winchester cases now in the 175gr area and all my LC cases are in charge he 185gr area . Welcome to the wonderful full world of reloading

You misunderstood my post sir. I'm talking about volume, the amount of water the case will hold. Not the weight of the case. The case weight can be all over the place. 8 gr of weight is nothing from brand to brand....But volume? 8 gr is a TON!

[Itsa Bughunt]

Hopefully someone new to hand loading will read this and avoid a catastrophic mistake.

Good to know. Me:Noob.

[Metal god]

Good call . although i did understand my brain farted on what i read

[Reloadron]

The water comes tomorrow.
I started a little test of my own on some cases. The problem is with commercial brass we really don't know when it was made but anyway I have weighed ten cases each of RP, Winchester, WCC 10, LC 13 and Federal. The cases were randomly selected from lots I have laying around. Each case was resized and the primers removed. So the weights represent ten each of resized brass with the same outside dimensions. The brass was also trimmed and the cases measure base to shoulder 0.400" datum 1.630".

RP
AVG WT 170.1
STD DEV 0.620
MAXIMUM 171.5
MINIMUM 169.3

Winchester
AVG WT 164.4
STD DEV 1.334
MAXIMUM 166.1
MINIMUM 162.4

WCC 10
AVG WT 177.9
STD DEV 0.586
MAXIMUM 178.8
MINIMUM 177.1

LC 13
AVG WT 178.8
STD DEV 1.870
MAXIMUM 181.0
MINIMUM 175.4

Federal
AVG WT 174.7
STD DEV 0.334
MAXIMUM 175.2
MINIMUM 174.2

The Remington and Winchester brass was taken from new brass I bought over 25 years ago. My guess is the brass can vary lot to lot from any manufacturer. I used modeling clay, the same clay I have used when doing stock bedding to plug the flash holes and primer pockets. Each tiny ball of clay added 1.8 grains to case weight. Tomorrow I'll fill the cases with water and do the conversion to cc units of volume for the cases. The case weights were less the primers, only the brass cases.

While all of this can be amusing as well as a PITA I have to wonder how much it really matters? I have yet to see a load manual that calls out loads by brass manufacturer. Has anyone ever seen a loading manual which mentioned case volume or brass manufacturer? Anyway, hopefully tomorrow I'll get some water in these 50 cases and see what the actual volume is on them.

Ron

[44 AMP]

Just out of curiosity, how did you measure your cases with water for volume??

The traditional method is to fill to the base of the neck, however, I have run into people who fill the case completely.

Either way, all that matters is standardization, and the realization that the water volume measurement is for comparison ONLY, and is not useful as a direct guide for reloading.

Weighing the brass is an equally useful comparison, though the actual numbers will be affected by the weight of the specific brass alloy used, where the water method is not.

Either way, the only conclusion is one brand, or batch has more volume than another.

If I did my math right, 8gr of water is 0.03 cu in. Enough to make working up loads important, but I don't think its enough to freak over.

[Reloadron]

Glad you mentioned where the cases get filled to. I plan to fill to the case mouth using tap water. I doubt the difference between tap water and distilled water will matter much. I will fill to the case mouth and only because it is easier to see. 1.0 gram of water is 1.0 cc of water in volume. 1 Gram = 15.4323584 Grains and I'll let Excel do the conversions. I also need to subtract the modeling clay.

Ron

[Metal god]

Weighing the brass is an equally useful comparison

In what way is it equal or what does equal mean to you ?

Equal meaning measuring case weight will tell you the same info as measuring H2o volume ?

OR

Equal meaning both methods are not helpful or equally helpful in reloading ?

[Stats Shooter]

.
While all of this can be amusing as well as a PITA I have to wonder how much it really matters? I have yet to see a load manual that calls out loads by brass manufacturer. Has anyone ever seen a loading manual which mentioned case volume or brass manufacturer?

According to my own experience and according to Quickload it matters a lot. If you look at my original post I mentioned that the pressure differential between RP and Norma brass, all else equal, at my current load is approximately 20k, enough to put you wayyy over MAP.

Moreover, my experience supports the software in that I simply cannot safely get the same velocity in RP brass as I can in Norma in my .300 wm.

Now, I do not sort cases by weight or volume within the same lot and brand. If the brand of brass I am using varies that much within lots then I'll switch brands.... Trigger time is more important for the competition shooting I'm doing than going from 1/4 MOA to 1/8 moa.

I'm not knocking those that do try and wring out that last 1/10", just that it doesn't matter that much in 1,000 yard Field Precision rifle when the X-Ring is 1/2 moa and my load is already 1/4 moa in unsorted brass/bullets.

But I believe case volume CAN matter a lot, especially if it is 9% lower/higher than other brands.

[Metal god]

I agree with Mississippi . I was loading some mixed 223 brass with a known load I worked up using a single head stamp case lot . Every once and awhile one of the cases would fill to the top of the mouth almost to the point of overflow . While the rest did not fill the case that high . I learned all the cases that "over filled were all the same head stamp . I kept them separate from the rest and they averaged about 100fps faster then the rest . I then did a H2o volume test on the cases and they had 2.5gr less volume then the others . In a 223 case that is HUGE and showed on the chrono . If you were to compare that to a 300 WM it would be around 7.5gr difference .

[Lucas McCain]

According to my old naval book of standards 1 cubic centimeter of water weighs 1 gram. 1gram is equal to 15.43 grains. So if you have 8 grains difference in water weight you have approximately a little over a half a cubic centimeter in volume.
There are 25.4 millimeters in 1 inch, so 10mm is .393 of an inch, for reference 3/8 inch is .375, so its about a 3/8 in. cube

8 grains of water volume then would be a rectangle shape very slightly larger than 3/8 by 3/8 square and 3/16 in height. Because gun powder has a different DENSITY than water I think the real question is;

How many grains does a 3/8 by 3/8 by 3/16 volume of gun powder weigh?

Correct me pleas if I am wrong, because what we are talking about is important.

[Nosler guy]

I've done volume comparisons by brand quite a few times since I collect most range brass I find and have a pile. Fed, rem and Hornady all rank pretty low in capacity which can be pretty useful for efficiency in a short barrel. I find that in combination with compressed loads often results in stellar velocities for short pipes.

The most important thing to gain usefulness from this knowledge would be what the pressure difference is per grain of capacity. I only have a( feel) for this based on experience but no real solid data chart to use.

Weight sorting brass is definitely important, to me anyway, but you can't always compare brands by weight. Just because 2 brands weigh the same doesn't mean they'll have the same capacity and capacity is the most important part in sorting brass.

Sent from my SM-N920V using Tapatalk

[Metal god]

Lucus can you break that down into cc ( cubic centimeter ) . my math is not that good but If we knew that I can use my Lee dippers to tell you what the powder amount would be with multiple powders .

[Reloadron]

According to my own experience and according to Quickload it matters a lot. If you look at my original post I mentioned that the pressure differential between RP and Norma brass, all else equal, at my current load is approximately 20k, enough to put you wayyy over MAP.

Moreover, my experience supports the software in that I simply cannot safely get the same velocity in RP brass as I can in Norma in my .300 wm.

Now, I do not sort cases by weight or volume within the same lot and brand. If the brand of brass I am using varies that much within lots then I'll switch brands.... Trigger time is more important for the competition shooting I'm doing than going from 1/4 MOA to 1/8 moa.

I'm not knocking those that do try and wring out that last 1/10", just that it doesn't matter that much in 1,000 yard Field Precision rifle when the X-Ring is 1/2 moa and my load is already 1/4 moa in unsorted brass/bullets.

But I believe case volume CAN matter a lot, especially if it is 9% lower/higher than other brands.

OK, so what did I base my comment on? I am not about to get into a discussion about Quick Load but suffice to say it is good stuff. Now tell me how quick Load derives those pressure numbers? The problem is Quick Load uses a software solution to get pressures. Now if it was just that simple to derive solid accurate pressure numbers why would SAAMI go through all the trouble and expense of Small arms ammunition pressure testing? Why would the CIP go through all their effort pressure testing? If it is as simple as running some data into Quick Load why do SAAMI and CIP each use a well defined method and explain that test method?

Now, nobody can deny that case volume figures into a pressure curve or more important the area under he curve. The question here is how much does it matter? Now the argument can be made that if the case volume for a given caliber mattered enough for the load data to come in light of its intended use that the load data should include volume of case and I have yet to see load data broken down by case volume or case manufacturer. If the variation in case volume matters that much why don't load manuals address that, aside from start low and work up with a powder charge? When a cartridge ignites in a chamber the brass expands to form into the chamber. Does the added volume as powder burns matter?

Mississippi, I read your other thread on Quick Load and as mentioned I see Quick Load as a good and useful software tool. I do question how Quick Load derives those pressure numbers it spits out? While they touch on their software solution they really do not get into the actual applied formula used. I just tend to question their pressure numbers based on what I have mentioned. If things were as critical as they sound I would think we would see more broken guns. Not that a gun will explode if we exceed the proof pressure but if things are all that dangerous why don't we see much more disaster?

Today I hope to get the water into the cases I mentioned and see what the case volumes are. The idea being will the cases which weighed more have less case volume with the outer dimensions all being the same.

Ron

[Reloadron]

Lucus can you break that down into cc ( cubic centimeter ) . my math is not that good but If we knew that I can use my Lee dippers to tell you what the powder amount would be with multiple powders .

The weight 1 gram of water has a volume of 1 cc. The gram is a rather large unit when looking at powder charge weight. There are 15.4324 grains in a gram. Making it rounded a little we can say 15.43 grains = 1 gram and 1 gram of water (the density of water going from weight to volume) equals 1.0 cubic centimeter of volume. There are a few variables but not enough to worry about such as water temperature and water purity. Tap water at room temperature is good enough.

Ron

[higgite]

Originally Posted by Lucas McCain

8 grains of water volume then would be a rectangle shape very slightly larger than 3/8 by 3/8 square and 3/16 in height. Because gun powder has a different DENSITY than water I think the real question is;

How many grains does a 3/8 by 3/8 by 3/16 volume of gun powder weigh?

The concern is not how many grains of gunpowder can you stuff into the extra 3/8 x 3/8 x 3/16 case volume, but rather how much should you adjust your powder charge to compensate for the larger (or smaller) case volume.

[Stats Shooter]

Ron:
I'm not going to quote all your text. But I agree with you to an extent. I think there are diminishing returns to some of this stuff like sorting by case volume to the 3rd decimal. But there is no doubt that case volume by brand can be very different.

I know that technically Lake City is 556 or 762, but use lake city brass vs something like RP in .223 or .308. I was doing a load workup one time for my AR-10 using lake city brass and CFE powder....I was getting near max velocity according to hodgdon at about 3.5 gr below max charge weight. I checked all my lake city (12) brass against my RP and found that the powder didn't come up as far. Meaning Lake City had less internal volume.

I will concede that I haven't done enough testing to say if more internal volume is better. Perhaps in some instances more volume is better, like with slow powders and long Barrels..And maybe less volume is best with light pills and short barrels so that you can fill the case.

But there is no doubt, and I think you agree (?), That there is enough volume variation in different brands of brass that you have to rework loads if you switch.

The concern is not how many grains of gunpowder can you stuff into the extra 3/8 x 3/8 x 3/16 case volume, but rather how much should you adjust your powder charge to compensate for the larger (or smaller) case volume

This was the main point of my original post. Thanks for summing it up

[Reloadron]

But there is no doubt, and I think you agree (?), That there is enough volume variation in different brands of brass that you have to rework loads if you switch.

Absolutely I agree. This is why when changing brass unless you know the new brass has the same volume as the old brass we work up a load, all over again.

Later today hopefully we will get to my water in these cases as I am curious.

Another interesting consideration is the powder. Once we get into the VMD (Volume Measured Density) of the powder. Lee publishes this data for use with their Lee Dippers but I have read where the guys making the powder allow a VMD change as much as 16% lot to lot.

It is very important that you repeat this process with any new container of the same powder because the powder companies allow themselves a 16% tolerance between batches. This can result in over charging if you work from the same setting and the next container of powder you get is more dense.

The above quote taken from here. How true that is beats the heck out of me. But it also figures into the case volume thing, especially for those looking for repeatability accuracy at long ranges. My belief here is the simple details which seem to not matter too much at 500 yards suddenly matter much more at 1,000. It's all about the variables.

Ron

[Stats Shooter]

. It is very important that you repeat this process with any new container of the same powder because the powder companies allow themselves a 16% tolerance between batches. This can result in over charging if you work from the same setting and the next container of powder you get is more dense.

I have never personally seen a difference that big. But I have seen 50 fps difference on a .270 win loaded with H4831 from one lot to another.

Along those lines, I wonder how much H4831/IMR 7828 long grain differes from the short cut versions.

[Reloadron]

I have never personally seen a difference that big. But I have seen 50 fps difference on a .270 win loaded with H4831 from one lot to another.

Along those lines, I wonder how much H4831/IMR 7828 long grain differes from the short cut versions.

Once I have the actual volume numbers for those 50 cases I mentioned I plan to load them and soon as we get a nice day take them to the range and over the chronograph they go. I will see what I get.

As to how much the VMD differs in the short cut versions? Beats me? I would think the burn rate changes only because the powder has a greater area in short cut grains. That would result, likely in a faster burn rate. Enough to matter? I haven't a clue. Also, while the chronograph is a very nice to have tool I don't think the velocity changes represent a large pressure change but I am not sure how much the pressure and actually the pressure curve effect velocity?

Anyway, after I get the water dried out of the cases I'll remove the clay and load them and see what we get. The good part is an excel spreadsheet has plenty of columns.

Ron

[JeepHammer]

Because of the popularity of Military brass, I'll throw this in the mix...
Brass as common as Milbrass it's worthy of mention.

Each brand of Milbrass (WCC, LC, etc) has different capacity,
And it's NOT in line with civilian common brass.
Older military brass has less case capacity, 'Generally'.

Since 2012, 5.56mm (LC 12 & newer) is closest to civilian brass.

There is still a BIG DIFFERENCE in 7.62x54mm military & civilian .308 Brass.
Some reloading manuals actually have different load recommendations for civilian vs. military brass (.308 cal vs. 7.62mm).

I have zero problems with using military brass, I just recommend working up loads specifically for Milbrass, and in particular up to 2011, and 2012 and later,
Watching when you change between WCC & LC.

[Reloadron]

Lucas McCain:

How many grains does a 3/8 by 3/8 by 3/16 volume of gun powder weigh?

Depends on the powder. Each smokeless powder has a VMD (Volume Metered Density). For example using the Lee VMD Chart Hodgdon H 335 powder has a VMD of 0.0645 so if I have a volume of 1.0cc I can say 1.0/.0645 = 15.50 grains of H 335.

Back in the very first post Mississippi mentioned H 1000 which has a VMD of about .07920 so a volume of 1.0 cc divided by the VMD 1.0/.07920 = 12.62 grains of H 1000 powder. Actually over 3 grains less than for the H 335. Then there is the other consideration of how much the VMD of powder can change lot to lot. Anyway, the weight of a given volume of gun powder will change depending on its density.

Ron

[44 AMP]

Equal meaning both methods are not helpful or equally helpful in reloading ?

Metal God, the answer is ..yes...

Both methods will tell you that one case has more, or less volume than another. That's ALL it tells you. After that, its up to you to do your load development.

I have yet to see a load manual that calls out loads by brass manufacturer.

I don't know what you're looking at, I have yet to see a loading manual that does NOT list the case use (by maker) for EVERY SINGLE LOAD THEY LIST.

Generally speaking its in the front part of the data section for each round. Along with primer used, and test firearm.