Have a puzzling question. I recently fired 15 6BR rounds, 5 of which the case necks did not expand. All cases are Lapua and on the fifth loading. All were annealed but the necks didn't budge. They should be .270 but are only .266. The neck walls are all .012. Any ideas? I'm going to send some cases to Alex at AMP, he's as curious as I am. I've replied to a couple post before but never posted. Thanks, if you have a solution.
Case necks not expanding
- Thread starter stifffingers
- Start date
Are they uniformly .266 throughout the neck cylinder, or does the ID vary as you move toward the shoulder from the case mouth?
I don't have an answer, but springback is an unpredictable thing, so I'd wonder if you're seeing neck walls that look reasonable, but a shoulder area that might have more clues were you to compare in cross-section.
I don't have an answer, but springback is an unpredictable thing, so I'd wonder if you're seeing neck walls that look reasonable, but a shoulder area that might have more clues were you to compare in cross-section.
Someoldguy
I believe the first question you need to answer is : what is your chamber neck diameter? Without this information, everything else is . . . speculation at best. And this needs to be a measurement, not information gleaned from the 'net'.
Someoldguy
Hate to 'beat a dead horse', but this is why the OP needs to know his neck measurement accurately. Otherwise, it's all just a guess.
swd
Silver $$ Contributor
This is important to know to answer to OP's question^^^
P.S. I'm loading with 29.7gr. VIT N-135 and 67.5grbt.
Yes ,I did and it was almost a waste of time. The results came out .2655 and .266 using a .270 bushing. Annealed necks will not spring back so we have to use the next size up bushing. I only size a portion of the neck, not the whole neck.
Correction. I'm loading 31.9 of N-135 with the 67.5 grbt.
I've never heard of "bad brass". What is it?
My Win. brass in the photo has been fired 18 times, no annealing.
The unsized part of the neck has expanded fully to the factory Rem 40x chamber. It no longer seems to have any spring back.
The mouth part of the neck gets sized smaller to hold the bullet. But on firing the neck mouth part (sized) never expands fully to the same diameter of the unsized , lower part of the neck.
When sizing with a bushing, no expander used, the spring back will be outward, if any at all.
The unsized part of the neck has expanded fully to the factory Rem 40x chamber. It no longer seems to have any spring back.
The mouth part of the neck gets sized smaller to hold the bullet. But on firing the neck mouth part (sized) never expands fully to the same diameter of the unsized , lower part of the neck.
When sizing with a bushing, no expander used, the spring back will be outward, if any at all.
Could be the brass was annealed unevenly. (more spring back on some cases not as much on others) If, as the OP states, "case necks not expanding" there would be powder residue on neck and shoulder..... Just a guess. Shynloco may have a different answer
Wouldn't that be "improperly annealed brass"?Could be the brass was annealed unevenly. (more spring back on some cases not as much on others) If, as the OP states, "case necks not expanding" there would be powder residue on neck and shoulder..... Just a guess. Shynloco may have a different answer
Hard to do it right (for me), so i don't anneal.
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