anyone seen hair-thin ring of trimmed brass at the bullet neck just after seating?

Normally it's a sign of no chamfering at all.

Sure you didn't miss doing a few??

rc

If the case walls are too thick and the seater die is too tight, or is set to crimp prematurely, jacket material will be shaved off the bullet, chambered or not.

I always helps to know more information such as what caliber, lead or FMJ bullets, press and dies.

If it is handgun or rifle?

Handgun could be not enough flare and you are shaving the bullet, but without more info, just guessing??

Could be lack of de-burring and/or over crimping.

Make sure the brass is de-burred as well as chamfered. Start over and re-set your seater/crimper die per instructions.

shekarci,
I'm guessing your talking about rifle brass, ("over-chamfering and/or over-deburring").
If it's only happening on a few of them check your case and make sure it's not over length. If it is, trim your brass. If not, back your seater die out about 1/4 turn and try again. If it gets better then continue to back the seater out 1/4 turn until finally no "hairs" are left. You'll end up with less crimp on some cases, however it will be sufficient. They will never have the same amount of crimp unless you trim to the same length.
Hope this helps!

Be Well,
Joe's

Yep, I've had it happen a few times when loading wheel gun cartridges. And since I meticulously trim, ream, and chamfer all my brass, I was able to identify, and eliminate the problem, which was caused by over crimping. No biggie, just back off the crimp a tad and it will go away.

GS

http://www.thehighroad.org/showthread.php?t=707429

Yes, like this. See pictures in post #5. I did not trim, chamfer or debur my brass. Happened on .357 loadings crimping to the cannelure. Simply wiped the brass hairs away with a cloth. They shot fine.

I have on a few occasions but they shot right along with the good stuff.

I've always deburred and chamfered my cases after I shoot them. I also take a bristle brush that has case lube on it and lube the mouths of the cases before seating. It seems to help stop those "slivers" from happening and makes bullet seating a little easier.

Factory crimp die

Yes, I've seen those.

It's either brand new brass, or brand new dies.

At least for me, that's the only time I've seen that.

Shear, when the case bell is removed by the seating die the bell can be larger than the dies ability to close it. Then there is a chance the case is not centered in the shell holder, in any case the die shears off part of the bell.



F. Guffey

I've seen this happen before with 9x19 and my solution was to back off the seating die a hair. No problems anymore.

Rifle? Not pistol? The new dimension die has a guide, I believe I would be hard pressed to find a Hornady New Dimension die that crimped.

That leaves 'roll over' brass at the neck of the case during case preparation.

F. Guffey