6.5 Creedmoor Waiting for components I weighed 4 (3) different brass

[MLS2GO]

I'm new to precision reloading and had some time on my hands while getting everything ready to load so decided for the heck of it to weigh some different brass I have shot from factory loads. I weighed 10 as a representative random sample and ran some numbers on them using sample Standard Deviation. I had Federal made American Eagle from the 120 OTM rounds, Federal Gold Match with the 130 Bergers, Hornady from 140 ELD, and Sellier and Bellot from 140 Tactical. I know Tactical. All were weighed as fired with the spent primers in, (remember I was waiting to get everything together). All in grains. the formula came down to 1/100s on the SD even though I measured on .1. Not sure that works statistically, but here's the data:
Am Eagle Avg 175.3 ES 1.1 SD .38
Fed GMM Avg 175.4 ES 2.1 SD .56
Hornady Avg 158.7 ES 2.8 SD .95
S&B Avg 167.3 ES 6 SD 2.0

The AE and the Fed GMM were small primer and the Hornady and S&B were large primer.
It looks as if both rounds loaded by Federal are the same brass by the measurements. One of the reasons I did this was to see if I should sort these from each other or just mix them. I intend to mix them.
The S&B are cheaper rounds made in the Czech Republic and shoot bigger groups than the others.
Unfortunately I bought a 6.5 in the shortage era and bought what I could get my hands on, not always what I wanted.

 

[Steel head]

Sorting by weight is useless.
Sort by volume.
I wouldn’t mix brands personaly.
Nor would I sort brass.

 

[gulada97]

You can go crazy trying to sort through your brass so they are within your "specs". I opened a box of Peterson match 308 over the weekend and measured every single one of them. The lengths were pretty inconsistent, so were the weights. Stick with the ones that shoot well and try not to mix and match. Prep them the same way, every time.

 

[Rob01]

What Steel Head said. Trying to weigh brass that isn't fully prepped is about the worst way and you will find out even less than weighing it prepped. It's a waste of time. Use good brass and load it. I have never weighed a piece of brass in all my years and load some very accurate ammo. Time is better spent elsewhere.