Many handloaders believe an accurate load starts with quailty brass. The more uniform the brass, the better accuracy you can expect. So there are a lot of questions that commonly arise:
- What is the best brass?
- Should I use “once fired” or “military surplus” brass?
- Is quality of Lapua brass really worth the added cost?
I stumbled upon some info on 6mmBR.com about a year ago containing some data that can be used to compare of brass uniformity between manufacturers. I’ve tried to refer back to article several times … but I always have a hard time finding it again, because it is buried in the middle of post with a lot of other info. Since it was so helpful, I thought I would summarize the findings here, and include some additional data visualizations to make it easier to “see” the difference (rather than just looking at a table full of numbers).
All of this data is for 223 Remington brass, which makes this an easy apple-to-apples comparison … but the findings are likely representative of what you would find with other cartridges as well.
|Manufacturer||Sample Size||Avg Weight (gr)||Extreme Spread (gr)||Standard Deviation (gr)|
|Lake City ’04||50||92.97||2.5||0.61|
The chart below illustrates the two most important criteria from these findings:
- Standard Deviation – Probably the most useful measure, because it essentially indicates how similar the weights were from one another (uniformity = accuracy). In general, standard deviation (SD) indicates how much variation or “dispersion” exists from the average. A low standard deviation indicates that the data points tend to be very close to the average, whereas a high standard deviation indicates the data points are spread out over a large range of values.
- Extreme Spread – Indicates the maximum difference found within the data points (i.e. the weight of the heaviest piece of brass minus the weight of the lightest piece of brass).
Here is a link to the article on 6mmBR.com containing the original information: http://www.6mmbr.com/223Rem.html