Reloads Weights

[Dwnw/theAltitudesickness]

TLDR: mixed brass reloads from brother vary by ~30 grains. Question for the group how much weight variation to expect in mixed/ unknown brass? How much weight variation in completely reloaded cartridges? What can/ should I do with the ones significantly from the standard deviation.

Long Story. My brother has typically reloaded for me- 30-06, Hornady SST 165 grains, powder 1MR4350 with 56 gr of powder. He has used one other powder at 58 grains. But in his last reloading session he "double checked" something and there was significant powder change???? He thought most of the cartridges were getting less powder.

I have historically shot a lot of reloads from him, and was having a few chambering issues in the past. I had developed a "fit", "tight" and "don't fit" sorting system. With the last batch I decided to weight out each bullet and group them as best as possible. I also decided to include these older groupings I had established. And surprised to see some of the "don't fit" have the highest difference in weight, (not fitting/ chambering is a different issue for a different time).

I have been using factory only for hunting past couple seasons. And have weighted factory cartridges and use those as a semi baseline comparison. I currently have zero reloading supplies/ tools. But am trying to find ways to diagnose/ confirm powder charges? Am I overthinking brass weights being close? I can't image there is + 30 grains extra powered in some of the cartridges.

 

[Chris in TN]

Brass from different brands and lots can and will vary in both capacity and weight. You can have two cases of different weights that will have the same capacity. You can have two cases of the same weight with different capacity.

Thirty grains, on a case the size of a 30-06, is frankly a lot of variation (eta: even for mixed brands). I'd say twenty grains would be reasonable, but not exactly conducive to good precision.

This sort of question, which is really unanswerable to the level of detail you want, without knowing a bunch of other details, is why I don't like shooting other people's reloads and don't generally give my own reloads out to anyone, even though I load each round with the knowledge that my own children will fire most of them.

ETA: and the thirty grain variation you mention, will completely hide any variation in the weight of powder charges or bullet consistency. Generally even if you 'throw' powder charges with a measure, you'll be within 0.2 grains, maybe 0.3 on an '06 sized charge, and bullets will tend to be within 0.1 to 0.2 grains, even for basic stuff like Hornady SSTs. Add all that up and you're looking at 30 grains of variance and likely only 0.5 grains of that is outside the brass itself.

 

[Dwnw/theAltitudesickness]

Thanks Chris. I like the way you approached this.

I was only weighting complete reloads. Dug around and found some empty brass, did see a delta of 23 grains in that sample size of 10.

Thanks again