Lapua 300 Norma Mag Brass Weight Sorting

[Ledd Slinger]

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.

 

[Willie]

Very nice job! I saw very similar results on my last sort of Lapua, but it was only 7-08 cases. The only thing I did different, was complete prepping and neck turning prior to weighing.

I also resort after two firings, resize and trim to same length. It's a lot of extra trouble, but it makes me feel better. The time, I put in, gives me good consistency, but I could probably
be better off just volume sorting.

Thanks for sharing!

 

[missed]

Where did you find the brass?

 

[Ledd Slinger]

Found it in the classifieds on a forum. Some guy just happened to be selling and I was lucky enough to get the jump on it. Dont know where he got it from

 

[Ledd Slinger]

Dont know if it matters, but the Peterson 300 Norma brass I was working with previously had a median weight of 311.5gr, which was 6gr lighter than the Lapua.

 

[ShaunBrady]

Dont knowing it matters, but the Peterson 300 Norma brass I was working with previously had a median weight of 311.5gr, which was 6gr lighter than the Lapua.

I've been looking for that bit of information, so thank you for posting it.

 

[rpierce]

Nice find. That 200 pieces will last you the rest of your life. Toughest primer pockets Ive seen.