6ppc ring around the neck?

[T Kop]

What the od of neck measure after firing and what does the seated bullet measure. What powder are you using. Are you annealing after sizing

 

[600-60x]

What does your nk measure after sizing and again with bullet seated.

.255-.260

 

[Tim Singleton]

What brass manufacturer?

 

[D Coots]

i have found out what the ring mark is
it’s not were the bushing stops bushing travels down to almost the neck shoulder point I know that because I can see the grease marks after sizing
It’s were the bottom of the flat based bullets stop i seat to touch
if I measure the sized neck above the ring .255
Below the ring .253 (see pictures)
So it’s just the top of the neck that is getting resized
So the reason for the ring is not a neck separation concern
I use a .256 bushing that gives me.255 o/d
Wall thickness.8
.255 minus .16
Gives me.239
.4 tension
So why are my bullets falling out (lol)
seem fine when I load them but I have had some heads come out just by taking the loaded round out of the box ?
68 grn fb bench marks
They are no longer in business
Bob white (shooters corner) had old stock I bought them to get started
They shoot well base measure.243+
Not that this should matter but I lube inside of the necks with neo2 always have this is a new problem
I anneal every time with an amp annealer


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How can you chamber a round with a .243 bullet in a .8 wall thickness case?