Question about carbon ring on cases

[C Valentine]

I have noticed lately that the carbon ring on my fired cases, while pretty even all the way around, is always located about .05 above the junction of the shoulder and neck. Should the ring be right at the junction and is it something I should remedy? Is my sizing die not set properly? Or is it just not something to bother with? I use the Lee Collet die unless my cases need FL resizing.

 

[bigedp51]

The soot you see is caused by combustion leakage down the case neck until enough chamber pressure seals the case to the chamber walls.
It also might disappear if the case necks were annealed, meaning if the case necks were softer, they would seal sooner and have less soot on them.

Also if you would do a workup load starting at the suggested starting load and work up, and observing the case necks you would see the soot progressively move up the neck as the pressure increases.

In car engine terms you have a very slight amount of blow by past the rings and nothing to worry about.........keep driving.

 

[C Valentine]

Cool! I just tend to pick up on tiny details that are different between the old and new barrels. As long as it's shooting well, I will just go back to trying shoot between heartbeats and learning how to call my shots! Never realized how much your heartbeat could make that tiny dot on the reticle move around on the target until I got this new scope. Something to be said for free recoil I guess. Thanks.

 

[LHSmith]

Cool! I just tend to pick up on tiny details that are different between the old and new barrels. As long as it's shooting well, I will just go back to trying shoot between heartbeats and learning how to call my shots! Never realized how much your heartbeat could make that tiny dot on the reticle move around on the target until I got this new scope. Something to be said for free recoil I guess. Thanks.

Free recoil, as I know it, is done from a solid front rest and rear bag with minimal body contact...usually just the trigger finger and thumb. If you have ANY movement from a heartbeat- you have way too much contact with the stock....even if your shooting @ 60 X.

 

[C Valentine]

Right. I shoot F/TR so I supposedly cannot shoot free recoil...I think the rifle must be in contact with my shoulder. Was just saying that is probably why some of the Open and BR folks shoot free recoil with as little body contact as possible. I still tend to have more contact than I should I think with my hand and shoulder and that is where I am picking up the heartbeat.

 

[ireload2]

As the case necks get harder from being resized and fired, the soot will go further down the neck.

If you anneal the case necks the case will seal quicker and the soot line will move up the neck.

 

[C Valentine]

As the case necks get harder from being resized and fired, the soot will go further down the neck.

If you anneal the case necks the case will seal quicker and the soot line will move up the neck.

Thank you! That is exactly what was happening, now I know why. I just started learning to anneal and on those cases and on new cases the carbon ring was higher. Happy to have learned something today!