SD and ES for cases with carbon in neck and without

[Petrov]

Hey, any one here do a comparison for SD and ES numbers for cases that have had the carbon inside the neck removed (SStumbling) and lets say regular corn cob tumbling which leaves it realtivley unmolested?
I know of at least one person here who has better numbers with carbon left in the neck.

 

[Supersubes]

Anecdotally it seems like the SS tumbler peeps are the only ones posting about issues. Seems like we have one of those threads one or two times a week around here.

 

[Petrov]

guy on Benchrest forums did a test for group size and SS clean necks did better but he shoots for groups at 300 yards and wasnt measuring velocity

 

[Steel head]

Anecdotally it seems like the SS tumbler peeps are the only ones posting about issues. Seems like we have one of those threads one or two times a week around here.

 

[straightshooter1]

Hey, any one here do a comparison for SD and ES numbers for cases that have had the carbon inside the neck removed (SStumbling) and lets say regular corn cob tumbling which leaves it realtivley unmolested?
I know of at least one person here who has better numbers with carbon left in the neck.

I've done some comparison with my .308 cases and find a significant difference in results between necks that are really clean from SS tumbling and vibration tumbling where the carbon is left on the necks. Where I notice a big difference first in on seating the bullets where the clean neck have much more resistance than those having the carbon coating. That apparently translates to a difference in SD's and ES's where I saw a bigger variance in ESs than SD's. That difference is much like I get when shooting virgin brass with same neck tension (though case capacity variance in virgin brass is responsible for some of that). So, I dry tumble using medium grain rice, which I like better that corn cob as the rice doesn't have the dust issue. If I happen to get hold of really dirty brass, I'll SS tumble them and use lube to seat bullets so that I get better seating consistency (same for virgin brass).