Some brass not bumping back

[Pdvdh]

When I've experienced no further shoulder setback in spite of turning the die further in the press, the base of the resizing die was bottoming out on the shell holder.
I had to remove some material off the bottom of the resizing die. Or shave some material off the top of the shell holder.

Once the base of the die contacts the top face of the shell holder, you won't get any further shoulder setback when screwing the die down further in the press.

Otherwise, the shoulder should be set back further, by lowering the die in the press. No brass case shoulder is tough enough to not shove back, when rammed up into a hardened steel resizing die.

 

[birddog 68]

Lapua brass once fired i doubt its work hardened

Agree with this but after one firing they need the shoulder bumped?

I had to remove some material off the bottom of the resizing die. Or shave some material off the top of the shell holder.

Once the base of the die contacts the top face of the shell holder, you won't get any further shoulder setback when screwing the die down further in the press.

I feel that this is a perfect explanation.

 

[Rick Richard]

I always consider the first firing of new brass no different than fire forming.…which is why I never use data from the first firing.

 

[bultinkle]

When I've experienced no further shoulder setback in spite of turning the die further in the press, the base of the resizing die was bottoming out on the shell holder.
I had to remove some material off the bottom of the resizing die. Or shave some material off the top of the shell holder.

Once the base of the die contacts the top face of the shell holder, you won't get any further shoulder setback when screwing the die down further in the press.

Otherwise, the shoulder should be set back further, by lowering the die in the press. No brass case shoulder is tough enough to not shove back, when rammed up into a hardened steel resizing die.

While this makes sense it's hard to wrap my head around why this is happening for such a small number of cases, and yet all the others have no issue being set back with no cam at all and over a full turn less die engagement

 

[Chas1]

When I've experienced no further shoulder setback in spite of turning the die further in the press, the base of the resizing die was bottoming out on the shell holder.
I had to remove some material off the bottom of the resizing die. Or shave some material off the top of the shell holder.

Once the base of the die contacts the top face of the shell holder, you won't get any further shoulder setback when screwing the die down further in the press.

Otherwise, the shoulder should be set back further, by lowering the die in the press. No brass case shoulder is tough enough to not shove back, when rammed up into a hardened steel resizing die.

Hade same issue with some 30-06 brass and Pdvdh is correct. It solved my problem.

 

[Polaris_Doc]

I had the same problem with a 300 WSM years back. Some cases where chambering perfectly fine, others were closing very hard to the point I galled the lugs. I was also camming over the Press and thought they were being pushed back, but that was before I had measuring tools. One day I happened to be sitting lower in a chair and could see daylight underneath the die between the shell holder. I was camming over, but it still wasn't making hard contact. Ends up being the Press was flexing enough to give the illusion of the shoulders pushing back but there is just that much deflection. Turned the die in about another turn and they cammed over harder, die moved to contact with the shell holder based on not being able to get a .001" feeler gauge underneath. Those cases chambered just fine after that. Now I use an AMP annealer on every single firing for all my brass. Now my limitations are how long the primer pockets hold up.

 

[doverpack12]

Are you absolutely positive it's the shoulder causing a tight chamber on those 6 pieces?
Did you measure all aspects of your brass prior to sizing and after sizing to see how well your die matches your chamber?

My bet is on the base of those 6 being a tight fit in the chamber and not the shoulder at all.

I ended up switching dies on a 300 WSM but before that I colored the case with a sharpie to find the problem spot. To verify I sanded just above the 0.2ish size line and suddenly they chambered without issue.
My father in law had a similar chambering issue but his was just below the shoulder.

 

[Litrfoot]

Redding shell inserts, or grind down your die.

 

[Willys]

Anneal with socket and torch - cheap , easy, as effective as expensive machines just not as fast and convenient. Count seconds to hint of dull red in darkened room and thats your anneal time. Not rocket science.

 

[Rflshootr]

If they fit in the gun with slight resistance, keep them separate, load them and shoot them again in a group with just those cases. Just some questions, what are you using to measure shoulder bump? Are you depriming before you resize to get an accurate measurement? De-prime, measure, then size.
The shoulders aren't fully formed after 1 firing.

 

[Beluebow]

Redding Competition Shellholders decrease the amount the shoulder is set back not increase it. This means they will make the situation worse not better.

If you set your die up with the #10 shell holder then work backwards each shell holder afterwards gives it more shoulder bump in .002 increments....it's good to test this before hand and see how much each shell holder actually moves the shoulder.

Other than when you set up a new die, how often do you need less shoulder bump? Everything flows forward and eventually work hardens.

 

[Pete Brunel]

Once fired lapua brass
243 win
Rcbs full length sizer

Most cases bumping back as expected 2-4 thousandths.

6 or so shoulder is not moving at all, even as I crank the die down a lot. Removing expander does not change anything.

Example

Fired case base to shoulder is 1.658

95% of my cases are 1.6535-1.656 which is what I was shooting for

6 cases are 1.6580 and won't budge. I've turned the die almost to camming now and there is zero change.

Why are some of these being stubborn? What am I not thinking about here? Is it my press flexing on hard brass?

They chamber ok with resistance, so I plan to just shoot them as of now

Suggest Redding Competition shell holders.

 

[Beluebow]

Annealing doesn't fix everything...some brass is just stubborn.....I have some 7/6.5PRC ADG once fired brass that is a pita!!

 

[bultinkle]

If they fit in the gun with slight resistance, keep them separate, load them and shoot them again in a group with just those cases. Just some questions, what are you using to measure shoulder bump?

Hornady comparator and mititoyo calipers

Are you depriming before you resize to get an accurate measurement? De-prime, measure, then size.

I've tried it both ways, no change

The shoulders aren't fully formed after 1 firing.

i don't like cases that have resistance for hunting, and these do that, so I wanted to bump them.