Ledd Slinger
Silver $$ Contributor
I recently purchased 200 pieces of new Lapua 300 Norma Magnum brass and finished weight sorting them. Not that this really means anything as far as case volume goes, but it is no doubt one of the indicators of consistency in brass. Thought I'd share my results.
Extreme weight spread across 200 cases was 2.88gr. This might seem like more than some are used to when weighing smaller cases like 6 BR, but when viewed as a "percentage" of extreme spread divided by median case weight, the variation is less than 1% which is really good.
All brass weighed on AND FX120i scale.
For overall extreme spread
Lightest Case: 316.12gr
Heaviest Case: 319.00gr
Median Case Weight: 317.56gr
Overall Variation: 2.88gr ÷ 317.56gr = .009 = 9/10ths of 1%
The two windows for sorting and cull point:
316.00gr to 316.98gr: 32 cases - Low = 316.12gr
- 27 of those cases were within .5gr of each other from 316.5gr to 316.98gr.
317gr to 318.50gr: 159 cases (half of 1% variance)
- If I were to set a 2gr spread window from 316.5gr to 318.5gr you could add an additional 27 cases to the 159 in the two windows above for a total of 186 cases. Those would all fall within 2gr of each other which is less than 2/3rd of 1% when compared against the median overall case weight.
Above 318.5gr (cull): 9 cases - High = 319.00gr
- Ranged from 318.58gr to 319.00gr
So for large heavy cases, the variation was actually very good in my opinion. Keeping in mind that none of these cases have been trimmed, turned, or prepped in any way.
I set my sorting windows to maintain LESS than 1% weight variance over median case weight on the extreme spread. Lapua definitely exceeded that setpoint for me on the 300 Norma Mag brass. Job well done as usual with Lapua brass
All case dimensions at the .200" line and primer pocket diameters are all within spec so no worries there.
I hope this info helps some of you in one fashion or another for getting an idea on the consistency of this brass if you are lucky enough to find some. Please share your results on Lapua 300 Norma Mag brass if you have had the chance to sort them as well. Thanks.
Extreme weight spread across 200 cases was 2.88gr. This might seem like more than some are used to when weighing smaller cases like 6 BR, but when viewed as a "percentage" of extreme spread divided by median case weight, the variation is less than 1% which is really good.
All brass weighed on AND FX120i scale.
For overall extreme spread
Lightest Case: 316.12gr
Heaviest Case: 319.00gr
Median Case Weight: 317.56gr
Overall Variation: 2.88gr ÷ 317.56gr = .009 = 9/10ths of 1%
The two windows for sorting and cull point:
316.00gr to 316.98gr: 32 cases - Low = 316.12gr
- 27 of those cases were within .5gr of each other from 316.5gr to 316.98gr.
317gr to 318.50gr: 159 cases (half of 1% variance)
- If I were to set a 2gr spread window from 316.5gr to 318.5gr you could add an additional 27 cases to the 159 in the two windows above for a total of 186 cases. Those would all fall within 2gr of each other which is less than 2/3rd of 1% when compared against the median overall case weight.
Above 318.5gr (cull): 9 cases - High = 319.00gr
- Ranged from 318.58gr to 319.00gr
So for large heavy cases, the variation was actually very good in my opinion. Keeping in mind that none of these cases have been trimmed, turned, or prepped in any way.
I set my sorting windows to maintain LESS than 1% weight variance over median case weight on the extreme spread. Lapua definitely exceeded that setpoint for me on the 300 Norma Mag brass. Job well done as usual with Lapua brass
All case dimensions at the .200" line and primer pocket diameters are all within spec so no worries there.
I hope this info helps some of you in one fashion or another for getting an idea on the consistency of this brass if you are lucky enough to find some. Please share your results on Lapua 300 Norma Mag brass if you have had the chance to sort them as well. Thanks.
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