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Rolling Shoulders

The other thing I have found with every single piece of new ADG brass is they ALL need chamfered and deburred from the factory. They have a noticeable rim around inside and out that needs removed. I run every single piece through my 3-way trimmer set to just clean up the case mouth. I have even seen some come with the neck not cut square. Mind boggling for a piece of brass that is supposed to be so good and "ready to load".
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I'm using a RCBS Gold Medal seating die. 300RUM ADG case and a 240gr Alco bullet. The first one went in without any trouble, than the next two did this. I've never seen this before, was wondering what the cause would be? Bullets have a coating of HbN.

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You seating due it's set up wrong way .you can't set up your seating die same way as your sizing die.
Put your case in the shell holder raise the arm and start turning your seating due till you feel the resistance. After back out the die 1 full turn and tighten it.
See if it works?
 
This to clean up neck tension or the die setting in press
That is what I was meaning, My Lapua brass that is packaged not as nicely as the ADG will always have a couple that the necks are dented slightly. So running them through the sizer will take care of that. Sorry for not being clear, as the discussion was already referencing neck tension, and die setting.
 
My Lapua brass that is packaged not as nicely as the ADG will always have a couple that the necks are dented slightly. So running them through the sizer will take care of that.
There are a couple of good options for this problem that only moves the necks - I've used the LE Wilson "new" mandrel (which I think is 0.015" under caliber) for multiple cases in the past, and I just got a 21st Century mandrel set that covers +0.001 to -0.003 in 0.0005" increments. My thinking is with the full set including two that are over-caliber I can straighten necks on new brass, fired brass, and after sizing to set the necks before seating.

The 21st Century set might help the OP, since he needs to expand the necks slightly the 0.0005 increment would help him get set with better control over the final sizing.
 
This May. Be. A. Seating. Due. Adjustment. Issue ! Try. Backing the Die Out A few. Turns. Then. Carefully. Slowly. Screw in. The. !
 
I talked to ADG and they told me their necks were on the tight side of their specs. They recommended opening up the necks more. They had issues like this when trying to seat flatbase bullets. So I'm in the process of getting something to do that from what was suggested here.
From talking to everyone and reading the replies I need to open them up to .3065-.307, since the bullets are measuring a hair under .308.
I chamfered the crap out of one and put some Redding dry lube on it and it still pushed the should out.
Thanks for all the replies.
 
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