Brass Separation Above Belt
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Rich Coyle
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How do you do it wrong when you install a shim between the die and the shell holder? I discovered by annealing the cases more often it sort of worked. Reloading, to me, is not science. It is a lot of art. That's why I check every sized case with the headspace comparator before I prime them.
I don't know what you are doing wrong. It's real easy and it works fine when I do it.
bigedp51
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The Redding competition shell holders work even better, to control and adjust shoulder bump you just change shell holders and never touch the die. And with these shell holders the die always makes hard contact with the shell holder with press cam over. Meaning this removes any slop from the press and more uniform shoulder locations.
Below the "air space" between the die and shell holder will cause any flex in the press to cause variations in shoulder location.
Below the "air space" between the die and shell holder will cause any flex in the press to cause variations in shoulder location.
J E Custom
Well-Known Member
I have read every post on this thread and there is still no agreement on the neck sizing issue, So I will try a totaly neutral approach and Let everyone decide which way they want to go.
There has been a lot of talk about case run out, cases laying in the bottom of the chamber, Banana shaped cases, Wall thicknesses, concentric cases, Bullets being centered that are only .001 thousandths out of dead center not making any difference, ETC.
So how do we solve these problems.
First = the chamber is the most concentric thing to the bore If done correctly by a good gunsmith. (Agree or disagree).
Next = If the bolt and action are blue printed correctly, the bolt face is absolutely square with the bore center line. (Agree or disagree)
And if the cases are neck turned and trimmed before they are fired the first time then they are centered and true with the bore because the chamber was true, even if the case body is not thickness perfect the neck will be aligned because it is true in wall thickness before you fire it and after it is fired because of the true chamber. The interior of the case body may not be concentric to the centerline of the bore because of the discrepancy in wall thickness that cant be dealt with. But the inside and outside of the neck will be concentric with the bore because it was uniform when turned and now the chamber has uniformed/centered it when fired and holds the case body in perfect alignment and square to the bolt face so it cant move. (Agree or disagree).
After fire forming, and before sizing there is no headspace. (Agree or disagree).
With proper dies and proper neck sizing without touching the case body
or the shoulder, The neck is still centered in the bore because the case body is holding it in alignment for several reasons, first with no head space it is pushing the case forward against the datum line (Shoulder) holding the case in perfect alignment with the chamber (Which is perfectly aligned because of the reamer quality and the smiths ability. (Agree or Disagree).
Next comes the quality of the dies, die set up and the loaders skill. with good dies and proper set up, and last but not least re loader skill, concentric ammo should be very possible and can be checked with a concentricity gauge, and with no change in the case body and the neck sizing is done correctly The ammo should be perfectly centered with the bore. (Agree or disagree)
Rifle accuracy starts with everything being as perfectly aligned with the bore centerline. The bolt body, the bolt raceway, the locking lugs on the receiver and the bolt, the bolt face, The action face to barrel shoulder and a perfectly centered chamber to bore center line. (Agree or disagree).
After going to all of this trouble the ammo should be as close to perfect
as possible and not Lay in the chamber with the bullet pointed anywhere but precisely down the center of the bore. The bullet relies
on the case neck to hold it in perfect alignment because it does not touch anything at the freebore and only the lands if loaded this way and even if loaded touching the lands the back of the bullet still relies on the case and the neck to align the back of the bullet. Another reason that some recommend the use of a concentricity gauge No matter how you seat the bullet. (Agree or disagree).
Many shooters may not be able to tell the difference in precision loaded ammo so it doesn't matter. (Agree or disagree).
Everyone has a choice of what's important or what's not (Agree or disagree).
Give your self an test and see how many Agrees or disagrees you end up with, then you will know where you stand on this issue.
J E CUSTOM
There has been a lot of talk about case run out, cases laying in the bottom of the chamber, Banana shaped cases, Wall thicknesses, concentric cases, Bullets being centered that are only .001 thousandths out of dead center not making any difference, ETC.
So how do we solve these problems.
First = the chamber is the most concentric thing to the bore If done correctly by a good gunsmith. (Agree or disagree).
Next = If the bolt and action are blue printed correctly, the bolt face is absolutely square with the bore center line. (Agree or disagree)
And if the cases are neck turned and trimmed before they are fired the first time then they are centered and true with the bore because the chamber was true, even if the case body is not thickness perfect the neck will be aligned because it is true in wall thickness before you fire it and after it is fired because of the true chamber. The interior of the case body may not be concentric to the centerline of the bore because of the discrepancy in wall thickness that cant be dealt with. But the inside and outside of the neck will be concentric with the bore because it was uniform when turned and now the chamber has uniformed/centered it when fired and holds the case body in perfect alignment and square to the bolt face so it cant move. (Agree or disagree).
After fire forming, and before sizing there is no headspace. (Agree or disagree).
With proper dies and proper neck sizing without touching the case body
or the shoulder, The neck is still centered in the bore because the case body is holding it in alignment for several reasons, first with no head space it is pushing the case forward against the datum line (Shoulder) holding the case in perfect alignment with the chamber (Which is perfectly aligned because of the reamer quality and the smiths ability. (Agree or Disagree).
Next comes the quality of the dies, die set up and the loaders skill. with good dies and proper set up, and last but not least re loader skill, concentric ammo should be very possible and can be checked with a concentricity gauge, and with no change in the case body and the neck sizing is done correctly The ammo should be perfectly centered with the bore. (Agree or disagree)
Rifle accuracy starts with everything being as perfectly aligned with the bore centerline. The bolt body, the bolt raceway, the locking lugs on the receiver and the bolt, the bolt face, The action face to barrel shoulder and a perfectly centered chamber to bore center line. (Agree or disagree).
After going to all of this trouble the ammo should be as close to perfect
as possible and not Lay in the chamber with the bullet pointed anywhere but precisely down the center of the bore. The bullet relies
on the case neck to hold it in perfect alignment because it does not touch anything at the freebore and only the lands if loaded this way and even if loaded touching the lands the back of the bullet still relies on the case and the neck to align the back of the bullet. Another reason that some recommend the use of a concentricity gauge No matter how you seat the bullet. (Agree or disagree).
Many shooters may not be able to tell the difference in precision loaded ammo so it doesn't matter. (Agree or disagree).
Everyone has a choice of what's important or what's not (Agree or disagree).
Give your self an test and see how many Agrees or disagrees you end up with, then you will know where you stand on this issue.
J E CUSTOM
Last edited:
Scooterbum
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- Jan 23, 2016
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This thread is about case head separartion. Start ur own thread.
MagnumManiac
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- Feb 25, 2008
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- 5,596
There is ONE and ONLY ONE cause for head separation, EXCESSIVE HEADSPACE!!
Whether it is due to the belt to boltface dimension, which should measure .220" and no more or less, or the head to shoulder position, the only answer is EXCESSIVE HEADSPACE.
With my match chambers, the belt headspace is held to .220" EXACTLY.
The shoulder, even with a match chamber, is a different animal, the shoulder usually stretches to .026" above virgin brass, and non-match chambers can go .035" or more.
If a mild load also caused a head separation, I would expect the belt headspace to be about right and the shoulder dimension to be too long.
The only way is to take a chamber cast and measure to be sure.
Hope this helps.
Cheers.
Alex Wheeler
Well-Known Member
One common misconception is that the neck aligns the bullet. The bullet is aligned by the freebore with usually only a couple ten thousandths clearance per side. That is why a looser fitting case will shoot better most of the time. Unless you can size a case neck and end up with zero runout, you will cause a bind with the bullet in the freebore, a little room in the chamber allows the bullet to center in the freebore without a bind. I recommend people go and test all of this stuff in their own rifles.
So, should the rear bearing surface of the bullet be out of the neck before it contacts the lands?
Alex Wheeler
Well-Known Member
The neck expands and releases the bullet, so even before the bullets begins to move the neck is letting go. I have tested case/bullet runout at 1k.
How do you determine the neck starts to expand before the bullet moves?
Alex Wheeler
Well-Known Member
If the bullet slides out of the neck pressure equalizes on both sides of the neck and the neck doesn't expand.
Scooterbum
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Alex Wheeler
Well-Known Member
If you would like to control the thread start your own, Sir.
