Brass Weight Comparison

V

ViperHRT

Private
Minuteman
Jan 14, 2022
27
6
New England
#1
I broke out a brand new box of Lapua .223 Remington Brass. As always, I measure random samples to insure they at the very least meet SAAMI specification. One measurement which caught my eye was the case weight. Most of the empty brass I've used to date weighs around 90 to 92 grains however he Lapua brass weighs 104 grains. While the Lapua brass is extremely consistent, it's quite a bit heavier than all my other brass. I put the following chart together which includes case weight, case length, and water capacity in grains. What was also surprising was the Lake City military brass was the lightest of the group.



I'm not accustomed to seeing cases this much heavier and the internal volume is indeed less which will impact the powder charge. I normally load 27 grains of Winchester 748 behind a 52 grain tip but according to Gordon's Reloading Tool this load is over the pressure limits. Dropping the charge weight from 27 to 26 - 26.5 grains puts me in a safer place.



I'm curious if anyone else has come across this situation and if so what are your thoughts and recommendations.

Thank you in advance!
 
#2
I have no experience with .223 brass but your findings are consistent with Lapua brass. You will likely have to find a different load and you’re on the right path. I’ve finally switched to Lapua for all my brass and have no regrets. In my opinion it’s the gold standard all others are compared to.
 
#5

I agree with this so much that I choose what caliber to build in part on whether Lapua brass is available for it. 300 RUM - dingo. 300 NM - bingo

Lapua is strongest (even though you give up capacity), and most consistent, thereby removing a variable (case volume) that you would otherwise have to chase if your SD were not acceptable. It lasts so damn long the increased cost pays off in spades.
 
#7
I purchased these about 10 or 12 years ago from Brownells if I remember correctly. The box is 100 count and the box has is labeled 4PH5009. The case head stamp LAPUA .223 Rem.
 
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#9
You're doing the right thing to measure case volumes before deciding how to load them up from a new batch of brass. I don't load for 223, but for the brass that I do, I always measure a good sample and find there's often a variance I have to deal with . . . especially if it's a different brand of brass I'll be using. Even within the same brand, there can be a significant difference that one just shouldn't take it for granted the case volumes are going to be the same; especially if one is loading close to max and there's significant differences in ambient temperatures to deal with.
 
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#10

Lapua Standard cases were always some of the heaviest in 223 Remington. The Lapua Match cases should be significantly lighter than what you have.






Lapua standard . . .






.....
 
#15
I probably have 15-18 kind of 223 brass. I have many of Lapua Match, Nammo, Nosler, Norma, Hornady, LC (new), Winchester, Federal, Starline 5.56, Starline 223, Sig, GFL, Ammo Inc, and alot of other brands.

Over 1000 cases of Lapua "MATCH" that I have, weigh around mid 90's, like 94-96. Zero cases are over 100 gr. The range I have seen in 223 over my life, dealing with tens of thousands of cases, is 89gr -104gr. The heaviest 223 case I have is from Starline. Its Starline 223 cases, which are pretty much 101gr-103gr for the lot I have. Starline 223 brass, from what I have, requires less powder, as its significantly higher pressure at same load than ANYTHING else I own. I have around 1000 of those. The Starline 5.56 is very similar in weight to many brands in the mid range, around 95-97gr.

The most case capacity, and the lightest brass I have is without a doubt the LC and the Norma. around 90 gr.

A normal 223/556 case internal capacity is around 30.2. But the light brass, they can go up to 30.38 or so, like LC.

I can see from what a lot of people are posting, that this is lot determinate. And it varies hugely it appears. A grid somebody posted, says Norma has among lowest internal capacity, however the 1000 I have, that is new, has among the highest I own above 30.3

I have heard about "Lapua" cases weighing 103 gr, but I have never seen one. I think they stopped selling that maybe decade+ ago, because all I have seen in last 10 years is "Lapua Match" which is either the same as Nammo, or extremely similar, weighing mid 90's gr range.

LC brass is a favorite among longer distance shooters, because you can get more powder in case, and that is an issue with the medium burn powers like Varget, being used....
 
#21

The standard cases are "match grade" quality. However, as my data above shows, they have a significantly smaller case capacity than typical Lake City cases. The original Lapua "Match" cases had case capacities nearly identical to Lake City cases and were intended to appeal to Higher Power Service Rifle shooters and other shooters were required as much case capacity as they could get in a quality case for loading heavy/long OTM bullets with extruded powders.

For some ungodly reason, Lapua has been slowly increasing case weight/decreasing case capacity of the Match cases.

...
 
#23
in 2015 i have lapua 223 brass weighted 93-97gr, now they are more or less 96-99gr.
they are getting heavier.

but the other day I shot one piece of 95,6gr and one of 99,2gr. both virgin brass, but different LOT and probably different year of production. and the difference in velocity with 80.5gr berger was 79fps!

I will repeat it...
 
#24
It's amazing how just a few grains in case weight can impact velocities so much and this will cause the point of impact to shift just due the increase or decrease velocities. In my case I suspect the velocity variation due to using Lapua brass will decrease along with the standard deviation along with group size. I just have to reduce the powder charge weight due to the case volume change.
 
#25
In an experiment to see what kind of difference I might get, I sorted 100 Lapua .308 cases (see pic below). Then I took the cases at each end of the spectrum and loaded them up to compared the velocities between those that weighed 172.0 and those that weighed 174.6-174.9. There was significant difference in velocities as well as POI's. When I compared cases weighing 172.8 and those weighing 173.1, I had no significant difference if velocities or POI; in fact, both those grouped really well and in the .3's. So, I've come to the conclusion that sorting by weight really does well in identifying the outliers to help get lower ES's.

 
#26
I completely agree with your assessment.

Although my focus is on Lapua brass, I may weigh my other brass to see if I can find 25 to 50 cases within 1/2 grain. This should provide me with nearly identical results in terms of velocity, SD, and accuracy.
 
#28
Just gotta keep in mind that though there is some correlation between case weight and case volume, with individual cases there can be case weights that are just the opposite where a case's higher weight can mean a higher volume instead of a lower volume due to variations in the distribution of the brass in the case. It's on the average of a group of case where one can find that correlation.
 
#30
With every 5.56/223 Remington brand in the velocity example I posted, the increase in case weight correlated to a decrease in case capacity/volume.




 
#32
Yes, and those are good illustrations.

And there can be significant differences in case volume within the same brand, as can be seen is this data from Peterson Cartridge Co.:

 
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