Black carbon in brass

[cet]

Howdy,

Been chasing an error when reloading for my benchrest rifles.
After loading 100 or so rounds, I usually do a random weight check of the completed rounds.
Lately, I've had to weight all my rounds as some were off by a margin.
To make a long story short, I found clumps of carbon in my brass, that added to my final weight.
I chased my field notes for hours and finally zeroed in on brass that was used with double base powders
VV550, VV140 and VV150.
Removed the carbon with a bronze brush, and behold, my weights are a lot closer.
The amount of carbon was suprising and pretty hard to remove.

Anyone else run into this problem before?

Thanks in advance

 

[Eagleye]

Howdy,

Been chasing an error when reloading for my benchrest rifles.
After loading 100 or so rounds, I usually do a random weight check of the completed rounds.
Lately, I've had to weight all my rounds as some were off by a margin.
To make a long story short, I found clumps of carbon in my brass, that added to my final weight.
I chased my field notes for hours and finally zeroed in on brass that was used with double base powders
VV550, VV140 and VV150.
Removed the carbon with a bronze brush, and behold, my weights are a lot closer.
The amount of carbon was suprising and pretty hard to remove.

Anyone else run into this problem before?

Thanks in advance

Heavy carbon buildup is usually due to loads that are on the light side, pressure-wise, thus incomplete combustion. [Dirty]
FWIW, VV N140 and N150 are single base powders, while VV N550 is double based.
Since I load most chamberings to their full potential, I have not experienced the issue in decades.
Regards, Dave.

 

[cet]

Heavy carbon buildup is usually due to loads that are on the light side, pressure-wise, thus incomplete combustion. [Dirty]
FWIW, VV N140 and N150 are single base powders, while VV N550 is double based.
Since I load most chamberings to their full potential, I have not experienced the issue in decades.
Regards, Dave.

Yup, only the 550 is double based.
That means all my VV loads, even the single base are making carbon.
You mentioned light loads, I do load some light stuff, by that I mean just above starting load
will that do it ?
BTW I keep my brass in original containers with #'s of firings
written on it, the brass loaded with Varget is clean, not a trace of carbon.

 

[floriosean1]

yup, increase the load slowly and cautiously a little, unless you start losing accuracy. Also ensure a good strong crimp to help with better combustion

 

[Trinimon]

One of the reasons I'm going to try out SS wet tumbling for my rifle cases. Pistols cases get clean enough in my vibratory tumbler with cob.