Neck Errosion?

M

markharp

Member
I am trying to improve my case prep. I think I might have too much variation in seating pressure. (use sinclair press and no guage)

What I have noticed is that many of my cases have small "pock" marks in the very leading edge of the case. At first I thought these were dents from hitting the edge of my die when sizing (embarrassing, but it happens) or bumping in the action. And I am sure this is the cause for some of the marks I see.

But with a little magnification, I clearly have little "pockets" or craters in the end of the necks on many. Can this edge erode? Ideas?
 
handle em with kid gloves!!

Does your action have cone breaching....if not they culd be dinging on the end of the case mouth while inserting them in the chamber without a bullet in place ....or while extracting if the ejector spring is tooo stiff....especially if the necks are turned and "thin"...these lil bumps or blems in the case mouth pucker up the wall thickness and give eratic neck tension.....very common with Rem/Win etc .....Roger
 
Boyd, max of about 15.

Piper, no. But I will be watching/feeling even closer for any breech contact. I do know that this was the case with some.

If I had the technology I would post some pictures, but literally have little round craters. Almost like sub surface gas popping in a plating operation or sub surface porosity in a casting being exposed.

Could I be jamming them into a piece of carbon in the throat? I will measure them, but I did find some cases about 5-6 thou longer than others. I have not checked to see if they were the ones with this condition.
 
How about excess case lube on the necks or buildup in the die.It's happenend to me on a long session and not paying attention :(
 
Deburring

Are you deburring too much.Possibly making the mouth too sharp allowing a small gas leak upon firing
 
I vote for dings from the ejection process.

Try removing the ejector plunger and see if it stops.

al
 
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