Does case weight affect load handling /reliability?


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<SLV>
January 1, 2008, 08:11 PM
I'm new to reloading. I just tumbled about 50 spent .30-06 shells from different manufacturers. I'm trying to keep very specific records, so I sorted the brass by headstamp and weighed a sample from each manufacturer. Within each manufacturer group I found the cases to be withing 0.2-0.3 grains of tolerance. However, each group was different from the other by 5-10 grains.

Is the heavier brass a better quality brand? Do you build hotter loads in heavier brass?

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USSR
January 1, 2008, 09:24 PM
<SLV>,

Regarding the groups of brass lighter or heavier by 5-10 grains, heavier brass will have less case capacity, so less powder will generate the same pressure and velocities as the lighter brass.

Don

<SLV>
January 1, 2008, 10:13 PM
That's good advice! I can't imagine that 5-10 grains of brass reduces the volume so much, but I might have to load 5 of each with the same charge and shove them through a chrony to compare. I might also fill each case with liquid and measure the difference.

Mark whiz
January 3, 2008, 12:31 AM
If you come across some military-spec brass, you'll find they they are even heavier (thicker) and will need a significant reduction in powder.
The old NRA general rule of thumb is to find the weight difference between the cases, multiply that by .12 (12%) and drop your powder charge by that amount. Say if you were loading cases that were 10gr heavier, 12% of that is 1.2 gr, so if your load for the lighter case was 46gr, the rough equivalent load for the heavier case would be 44.8gr (46-1.2=44.8).

SlamFire1
January 3, 2008, 12:43 AM
Is the heavier brass a better quality brand? Do you build hotter loads in heavier brass?

If you are loading maximum loads case weight makes a difference.

I like heavier brass, I just believe the case head is thicker, and I like a little more material there.

I have weighed 30-06 brass, and found that weight varies all over the place depending in manufacturer and date. I had some 200 grain WWII cases.

USSR
January 3, 2008, 08:42 AM
SlamFire1,

Yeah, I'm match prepping LC M72 Match brass right now, and they weigh anywhere's from 189.0gr to 196.0gr.

Don

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