Brass Weight vs Case Capacity

J

jwrowland77

New member
I wanted to do a little write-up tonight for the group with results shown.

Brass Weight vs Water Capacity

I shot a workup yesterday in .223 for my daughter using 69gr TMK, using mixed (year) LC brass with CFE 223, Varget and IMR 4895. Well, I had decent results yesterday as you can see in the pics. So I decided to do a little weighing tonight and just do a little further investigation. Targets were at 200yd, and rifle was shot off a bipod and rear bag

Rifle: Brand new out of box Savage Axis Heavy Barrel

Scope: Weaver 8-32x50

CFE 223 (Group .385" 0.18 MOA)

Brass weights: 93.2, 92.5 and 90.8. As you can see, the weights were all over the place.

Water Capacity: 30.8, 30.9, 30.8. As you can see, two were exactly the same which would explain the two holes right on top of each other.

Varget (Group .507" 0.24 MOA)

Brass weights: 92.2, 91.6, 92. Fairly close in weight.

Water Capacity: 31.1, 31.7, 31. Hole a little further apart but the difference could be shooter error.

IMR 4895 (Group .723" 0.35 MOA)

Brass weights: 92.1, 91.1, 92.0. Two fairly close and one a grain less.

Water Capacity: 30.9, 31.2, 30.8 this could explain two hole right on top of each other and one out in left field.

My humble conclusion: it is much more important to find the H2O capacity than it is to group like weights, as you can see by the results, especially in the CFE 223 group.

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Yup, especially when comparing different headstamps, there is no direct correlation between case capacity and case weight.

Go here and scroll down to "223 Rem Case Weight vs Capacity".

http://www.6mmbr.com/223rem.HTML

Weighing a case tell you one thing, how much it weighs, has nothing to do with capacity.
 
steve4102 said:
Yup, especially when comparing different headstamps, there is no direct correlation between case capacity and case weight.



Go here and scroll down to "223 Rem Case Weight vs Capacity".



http://www.6mmbr.com/223rem.HTML



Weighing a case tell you one thing, how much it weighs, has nothing to do with capacity.
Click to expand...


Oh yeah, I've read that thread several occasions. I always use capacity.

I mainly wanted to write it up because a lot of folks weight sort, which tells absolutely nothing, and I wanted to pass this test and results on to folks, especially new folks into precision reloading.
 
Thanks.

I also tested my 223/5.56 brass for capacity vs Weight and posted it several times. I was going to include my personal data as well, but it seems to be lost is cyber space.
 
Found it.

Here is my current stash of 223/5.56 brass.

GFL(223) dry weight-102.4gr
With H20-131.4
Case capacity in grains of H20-29gr

Remington(223) Dry weight-95.2gr
With H20-125.1gr
Case capacity in grains of H20-29.9gr

LC(5.56) Dry weight-96.3gr
With H20-126.7gr
Case capacity in grains of H20-30.4gr.

Note: that the LC 5.56 brass weighed 1.1gr more that the Remington 223 brass.
The heavier LC brass had .5gr More capacity even though it weighed more.
 
Interesting. Thanks steve4102!

I would have never thought that Rem brass would have less capacity than LC brass....of course I've never checked those before or even tried to load precision .223 ammo. I've only loaded hunting ammo which doesn't quite require the same level of precision.
 
Weight-sorting does serve a purpose, if you're working with a single lot of brass - particularly Remington or Winchester brass, which often shows 5 to 8 different peaks in the curve:

Weight-sorting groups cases together that likely came from the same set of drawing dies. As such, it saves a helluva lot of time if you want to get picky enough to check case capacity.


Range brass?
Once-fired brass from an outside source?
Miscellaneous mixed headstamps?

...Yea, don't waste your time. Your time would be better spent trying to calculate the standard deviation for the number of urine dribbles left by customers of the middle urinal at the last men's restroom in the International terminal at Salt Lake City International Airport.



And, there's a secondary, minor benefit. Although case weight is not a definitive indicator of case capacity, it will generally give you a good idea of where that lot will fall within the range of case capacities commonly encountered.
If you throw a Lapua case on the scale, for example, and it weighs 102 grains ...you're probably looking at notably diminished case capacity.
In contrast, something that weighs 93 grains is likely to be of fairly average capacity.
 
I did the loads for F-Class match loads. Trying to hit a 3" circle @600yd.

These were once fired from an outside source as I had bought the cases from someone else. I just used a little elbow grease and a lot of time in case prep. It makes a difference. As a matter of fact, I've never used anything but once fired brass that I've bought online.
 
I did the loads for F-Class match loads. Trying to hit a 3" circle @600yd.

These were once fired from an outside source as I had bought the cases from someone else. I just used a little elbow grease and a lot of time in case prep. It makes a difference. As a matter of fact, I've never used anything but once fired brass that I've bought online.
Click to expand...
Mixed brass.
Unknown origin.
Lots of case prep.
Surprised by differing case weights and capacities.
F-class.


These parameters are not compatible.
 
FrankenMauser said:
If you throw a Lapua case on the scale, for example, and it weighs 102 grains ...you're probably looking at notably diminished case capacity.
In contrast, something that weighs 93 grains is likely to be of fairly average capacity.
Click to expand...

Yet the chart in the Link posted in #2, disproves this theory.
 
:confused: A side question on water capacity. When filling a case with water, how does one know when "full" is reached. What I'm thinking about is how water will "over fill" a case in a little "dome" due to surface tension (I noticed some "domes" over 1/16" over the case mouth). so, depending on how big the "dome" is the water weight can vary quite a bit. Wrong? :confused:
 
I put a drop or 2 of dish or hand soap in the water that I use to fill the cases and that breaks the meniscus so the water level "flattens out". Then you can fill each case "flat" to the brim.
 
I generally fill with a syringe that way it doesn't over fill. I'll barely touch a paper towel to the top to get rid any dome (if any). Secret is to fill it slow.
 
I wonder if anyone has used anything else like say cream of wheat to find case capacity. No overflow, nice and neat at top, no droplets on outside of case....just sitting here at work thinking....

The downfall I could see is that not all pieces are exactly the same.

Upside, no water droplets on outside of case, all/most air pockets inside should be filled up.

Thoughts.
 
Case capacity relates to case weight how?

Steve 4102, I looked at the table you mention in post #13 that is linked in post #2. I believe it shows clearly that as case weight goes up, case capacity goes down.

It also shows clearly that the two are not locked together in a way that is terribly useful to the discerning handloader, so I do take your point. Measuring the primary object of your attention (capacity) is always superior to measuring a proxy (case weight).

I wonder if the O.P. weighed the brass with primers in place (probably, else the water would leak out) and if primer weight makes much of a difference? I also wonder if the cases were sized and trimmed before the water capacity was determined? How much care was taken to ensure temperature was controlled and air bubbles prevented? Was powder reside inside the cases a factor?

These are just the wrinkles in the measuring process I could think of immediately.

Just covering all the bases, I am,

Lost Sheep
 
Lost Sheep said:
I wonder if the O.P. weighed the brass with primers in place (probably, else the water would leak out) and if primer weight makes much of a difference? I also wonder if the cases were sized and trimmed before the water capacity was determined? How much care was taken to ensure temperature was controlled and air bubbles prevented? Was powder reside inside the cases a factor?



These are just the wrinkles in the measuring process I could think of immediately.



Just covering all the bases, I am,



Lost Sheep
Click to expand...


Actually, cases were cleaned in a sonic cleaner, fairly clean but slight residue left in the case since I don't have a SS rotary case cleaner.

Primers were taken out as I did not want that to affect the weights. I used these primer pocket plugs that can be bought from 21st century. Plugged the pockets, weighed, filled with water, then weighed again. Difference was case capacity.
 
Lost Sheep said:
Steve 4102, I looked at the table you mention in post #13 that is linked in post #2. I believe it shows clearly that as case weight goes up, case capacity goes down.





Lost Sheep
Click to expand...


I have found a weird situation in my .308 cases where, the Win cases averaged around 155gr with my Hornady cases weighing 165gr. However, the case capacity were exactly the same.
 
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