What's the deal? Necks (see pic)

[Shooter13]

This is a no turn neckwith .002 minimum clearance. So why are the so dark? We're running 3250fps in the 6 Grendel and have won several local matches and I'm not worried about "looks" per say. I know in some threads they have said "under pressure". So help me out. Oh, and I anneal every firing.
6 Grendel, BAT action (bolt), Bartlein barrel 12 twist, 80 grain bullets and 8208XBR powder, have I left anything out?

 

[gunsandgunsmithing]

Some soot on the neck is normal. Some cases show a distinct sine wave around the neck but I've never had that with my 6 Grendels, but I have my 30 Majors...same case!
I think it's a combination of things but mostly the thicker brass of the no or min turn Grendel case. Again, I do get them with the 30 version that is a tight neck and has thinner necks. Ultimately, I pay it no attention as long as it shoots well.
Otherwise though, your case looks a bit over annealed, to me.

 

[Shooter13]

Some soot on the neck is normal. Some cases show a distinct sine wave around the neck but I've never had that with my 6 Grendels, but I have my 30 Majors...same case!
I think it's a combination of things but mostly the thicker brass of the no or min turn Grendel case. Again, I do get them with the 30 version that is a tight neck and has thinner necks. Ultimately, I pay it no attention as long as it shoots well.
Otherwise though, your case looks a bit over annealed, to me.

Yes but you think a case annealed once it too much! LOL Hey thanks, I started to tag you in this but knew you'd see it. I have the sine wave on the 30 Major, I may micro turn these (or a few of them) just to see, will be easy to keep them separated. @gunsandgunsmithing what do you think of trying maybe in the spring and check groups? Now be nice, I know, no better than I shoot it probably won't matter but it might keep me sane this winter!

 

[whatsupdoc]

If you have a borescope check for a carbon ring. What resizing die are you using?

 

[Shooter13]

If you have a borescope check for a carbon ring. What resizing die are you using?

I keep the cabon ring at bay! Harrells die

 

[Shooter13]

I washed brass in dawn and Lemi-shine, no pins and here is how it looks now

 

[JMayo]

Is say Normal. EDIT ...

I put my glasses on and i think i see that that shell pictured sealed at the bottom of the sholder. That is not normal at all
Seal happens fully at neck shoulder junction on my 6bra.

Head space, low charge/pressure, hard brass comes to my mind.

 

[mikecr]

Either excess neck clearance or excess trimming from chamber end can cause it.
I wouldn't like it, or accept it as normal. But I guess that's just me.

 

[SmokinJoe]

This is a bolt gun or AR?

 

[KMart]

This is a bolt gun or AR?

6 Grendel, BAT action, Bartlein barrel 12 twist

 

[Shooter13]

Bolt

 

[Webster]

Yes but you think a case annealed once it too much! LOL Hey thanks, I started to tag you in this but knew you'd see it. I have the sine wave on the 30 Major, I may micro turn these (or a few of them) just to see, will be easy to keep them separated. @gunsandgunsmithing what do you think of trying maybe in the spring and check groups? Now be nice, I know, no better than I shoot it probably won't matter but it might keep me sane this winter!

Looks like heat tint and not soot. Unusual that with that dark color which indicates a high temp the color doesn't come down the body very far? Are you using a MAP gas torch. A MAP gas flame is much hotter than a propane flame?

 

[Shooter13]

Looks like heat tint and not soot. Unusual that with that dark color which indicates a high temp the color doesn't come down the body very far? Are you using a MAP gas torch. A MAP gas flame is much hotter than a propane flame?

AMP anneal. did you see the lower pic where I cleaned?

 

[WyleWD]

I have a couple of 6 Grendels too. When I tried 8208 in the 80's it blackened the necks up just like the one you pictured. It shot pretty well so I just cleaned it each firing. Now when I began shooting 66gr and 68gr in those same barrels about 75% of that went away. JME. Maybe let Mike anneal em for you. LOL. WD

 

[gunsandgunsmithing]

AMP anneal. did you see the lower pic where I cleaned?

Remember, some of the color/discoloration is in fact oxidation. Lemishine removes some oxidation. A better way would be to clean before annealing, if the goal is to see the amount of discoloration created by the annealing. But!!!...IME, if I significantly change the color, I've over annealed.

The bottom pic shows a pretty fair amount of discoloration, even after cleaning some of it off.

 

[gunsandgunsmithing]

I have a couple of 6 Grendels too. When I tried 8208 in the 80's it blackened the necks up just like the one you pictured. It shot pretty well so I just cleaned it each firing. Now when I began shooting 66gr and 68gr in those same barrels about 75% of that went away. JME. Maybe let Mike anneal em for you. LOL. WD

Now that's funny, right there!
But you know what, I agree that my lt32 load with 68's does show it less than my 8208 and 80gr loads. The flip side is I still get it quite a bit with other powders. I really think there are multiple factors at play. The thick brass and the relatively short neck both add stiffness to the neck. fwiw..Again...how's it shoot?

 

[gunsandgunsmithing]

I don't think the brass is ruined at all. I'd shoot it 2-3 times without annealing at all and see how it does. My guess is that it gets even better on the 2nd and 3rd firing. Oh, and don't clean the necks spotlessly clean inside either. I like a little carbon left. Hit em lightly with a nylon brush or just leave em alone.

 

[Shooter13]

I don't think the brass is ruined at all. I'd shoot it 2-3 times without annealing at all and see how it does. My guess is that it gets even better on the 2nd and 3rd firing. Oh, and don't clean the necks spotlessly clean inside either. I like a little carbon left. Hit em lightly with a nylon brush or just leave em alone.

That is the plan!

 

[6.5 forever]

Is say Normal. EDIT ...

I put my glasses on and i think i see that that shell pictured sealed at the bottom of the sholder. That is not normal at all
Seal happens fully at neck shoulder junction on my 6bra.

Head space, low charge/pressure, hard brass comes to my mind.

I vote low-pressure.

 

[gunsandgunsmithing]

I vote low-pressure.

If I didn't know better, I might agree. But trust me, that's not it in his case. Again, it's not an issue if it shoots well and it does.