Soot mark on brass

[blvedere]

Does ant one have any idea what would cause this type of mark on my case necks. Pics aren't very good but soot marks are very pronounced. They look like a sine wave going around the nesk.

 

[treeman]

looks pretty normal to me

 

[roninfl.]

Yep, looks normal to me also.

 

[timeout]

If you do not get the soot all the way down the neck, chances are that there is not enough clearance between the neck and the neck chamber of the rifle. So I agree, those in your photos look fine.

 

[fdshuster]

Those "soot" marks are nothing more than carbon produced by the burning powder. The same carbon buildup that occurs in the bore. Completely normal, and in the pictured examples, minimal, indicating that a cleaner burning powder is being used.

Try some really dirty ball powders like Winchester 748, and the entire case neck will be coal black!

 

[CaptainMal]

Your cases must fit tightly to into the chamber neck. Real good.

 

[Jay Christopherson]

Does ant one have any idea what would cause this type of mark on my case necks.

firing them?

Sorry, couldn't resist....

 

[22BRGUY]

All of the above...+4

 

[blvedere]

I turned the necks of my brass (30 BR) to .326", loaded they measure .328" my chamber is .330". Do any 30 BR shooters think this is to tight ?

 

[fdshuster]

Those are pretty much the standard dimensions that is the most commonly used. Same as what I used for my 30BR. You do not have a problem.

 

[22BRGUY]

If your loaded rounds measure .328 and your chamber is .330, thats .002 clearance. I don't shoot 30BR, but for me that would be just a little on the tight side. .002 isn't much space for expansion but with "springback" maybe you wouldn't have to resize much if at all. For safety, I have always wanted at least .003 but to each his own.

 

[blvedere]

Thanks for all your reply's, you to jaychris. coexist ?

 

[GPat]

The sine wave soot marks mean that you are getting a good seal on the chamber's neck and your necks are turned perfectly. That's what I was always told anyway.

 

[Jay Christopherson]

Thanks for all your reply's, you to jaychris. coexist ?

Take a close look at the logo's that make up "coexist" in my signature...

Here's a larger image:

 

[blvedere]

I stand corrected, old eyes, I am in the 4th Quarter and the game time is getting shorter. Bob

 

[gmorganal]

I believe that you will find that the sine wave appearance you observe on your cases corresponds to the lands and grooves in your barrel. You should have the same number of dips and rises in the sine wave as you have lands and grooves in your barrel.

 

[blvedere]

.

Take a close look at the logo's that make up "coexist" in my signature...

Here's a larger image:

WOW! Would make a great bumper sticker. Can it be reproduced? Is there any thing, legal, preventing me from having some made ?