Case is telling me a story, what is it?

[bigedp51]

The stretching and thinning of the brass is caused by the amount of "head clearance" or "air space" you have between the bolt face and the rear of the case. And this will cause a case head separation and case failures.

A resized case with .001 to .002 shoulder bump (head clearance) can stretch to meet the bolt face and spring back and not stretch past the elastic limits of the brass case. When you over resize your cases they have further to stretch to meet the bolt face and over stress the brass past its elastic limits.

Your dies instructions tell you to make hard contact with the shell holder and have the press cam over, and this is to ensure the resized case will fit any chamber. When reloading for just "YOUR" chamber you want to keep the shoulder bump to a minimum to make your brass last longer.

I full length resize all my cases because if full length resizing is done properly there are "NO" benefits to neck sizing only.

If your case is over resized with too much head clearance it will stretch and fail with very few reloadings. The example below shows a commercial .303 British case being fired in a military Enfield rifle with its longer headspace settings and "STRETCHING" in the base area.

The factory loaded Winchester .303 British case below was fired once and stretched .009 on the first firing. It was full length resized with the die making hard contact with the shell holder and the press reaching cam over. This case lasted for two reloadings and failed after the third firing. I have .303 Britich cases that have lasted for 32 reloading and only fail from neck splits by minimum resizing and below max pressures.

Below shows the rear of the case with minimum head clearance when fired and "NOT" stretching and thinning in the base area.

Bottom line, do not push the shoulder of the case back excessively when full length resizing and keep your chamber pressure below maximum and your cases will last much longer.

 

[farmboy108]

Tapered cases tend to grow more than straight walled cases a 220 swift is considered one of the worst as far as case stretching goes. The head separating like that is not good but in a modern gun you should not get hurt but I would toss the old brass and get a new batch.

 

[Lefty Dick]

Get a Lee Collet die.

 

[bigedp51]

A Lee collet die will NOT teach the OP the proper methods of reloading and longer case life. What the OP needs at a minimum is a case gauge like a Wilson case gauge in the rear of the photo, if you want a even more accurate reading then get a Hornady cartridge case headspace gauge like below front.

If you only push the cases shoulder back .001 to .002 shorter than its fired length the brass can not stretch and thin in the base web area.

Below are Redding competition shell holders, they allow the die to make hard contact with the shell holders and the press to cam over and still make adjustments for shoulder bump.

Below on the right is a standard RCBS shell holder, on the left is a Redding competition shell holder that reads +.004. This shell holder has the deck of the shell holder .004 lower than a standard shell holder meaning it will push the shoulder of the case back .004 "LESS" than standard. This Redding set contains five shell holders from +.002 to +.010 meaning they give you from .002 to .010 LESS shoulder bump. Once I have my full length die adjusted to give .001 or less neck runout I do not have to touch or adjust the resizing die and all shoulder bump adjustments are made with the shell holder.

 

[ykkid]

Probably a good idea to start fresh with new brass. You just never know how many times second hand brass has been re-sized, what kind of loads were run in them, if they are all of the same general reload count, if they actually were all just fired in the one rifle, and a bunch of other variables. since you rightly have great expectations for accuracy for the .220, the cost of one hundred shiny new cases all of the same lot number, all fired only in the rifle you own, and either only neck sized, or if you need to bump the shoulder on occasion, done minimally by yourself.

"Once-fired" brass purchased commercially is an act of faith. And although you may have received the brass from an individual you know and trust, he may have made the same act of faith years ago.

 

[bearhunter]

So I need a die that only deals with the neck now? What is the name I look up?
Neck sizing die?
Wow.. scary looking brass.

If you are only loading that particular cartridge for one rifle, just turn your full length resizing die back until only the neck is sized. I usually leave a little bulge on the bottom of the neck and size to one caliber(that means one diameter of the bullet) any more than that isn't really needed. Long case necks are hold overs from times gone by when chambers could be radically different even though they were cut for the same cartridge. The extreme tapers were designed to facilitate easy almost fall out extraction. By neck sizing to only one caliber it also ensures a center to axis fit in the chamber if your dies/press/shell head holder are true to their axis as well. One other reason for long necks had to do with the quality of the brass used way back when. Case necks would develop small spits or and in some cases issues with bullets coming loose. The Brits and others had so many issues they also stamped the necks with indents.

ykkid is right. toss the rest of that brass and start over.

 

[Pyd]

New brass it is.
This rifle came with about 10 boxes of reloads, each box has the load data written on it.
After I fired a box or two I decided to reload, cleaned the brass, set my die to do a full length resize without a crimp, and started.
Looking back, the resizing process required a lot of effort, it led me to believe the cases were only being neck sized before I got them, I could be wrong.
A year after getting the gun I ended up with the original dies the owner used with the gun, RCBS.
I thought I had read everything I could to get started safely, this head clearance is not a term I have encountered. It makes me wonder.. After inserting the primers I set the cases on a plate of glass, some sit flush, others wobble as though the primer is not seated fully. I took great care cleaning primer pockets, and during the seating.
Looks like new Norma brass can be had for a buck a piece, but I need to get a better grasp on the "head clearance" topic, as well as what is meant by "bumping the shoulder", I get the concept, but not so much how I can control it with precision. Otherwise I will just wreck the new brass too.
I have some new words to run through Google, so thanks. That video explanation of head clearance was pretty awesome as well.

 

[f-lock]

Loaded to many times?

2nd this! Just wondering how many times you have reloaded the brass your using?

 

[Pyd]

Me, once. But the bass came used. See post 2 up.

 

[silverfoxdj]

Tagged nice illustrations Ed..

 

[LouF]

The stretching and thinning of the brass is caused by the amount of "head clearance" or "air space" you have between the bolt face and the rear of the case. And this will cause a case head separation and case failures.

A resized case with .001 to .002 shoulder bump (head clearance) can stretch to meet the bolt face and spring back and not stretch past the elastic limits of the brass case. When you over resize your cases they have further to stretch to meet the bolt face and over stress the brass past its elastic limits.

Your dies instructions tell you to make hard contact with the shell holder and have the press cam over, and this is to ensure the resized case will fit any chamber. When reloading for just "YOUR" chamber you want to keep the shoulder bump to a minimum to make your brass last longer.

I full length resize all my cases because if full length resizing is done properly there are "NO" benefits to neck sizing only.

If your case is over resized with too much head clearance it will stretch and fail with very few reloadings. The example below shows a commercial .303 British case being fired in a military Enfield rifle with its longer headspace settings and "STRETCHING" in the base area.

The factory loaded Winchester .303 British case below was fired once and stretched .009 on the first firing. It was full length resized with the die making hard contact with the shell holder and the press reaching cam over. This case lasted for two reloadings and failed after the third firing. I have .303 Britich cases that have lasted for 32 reloading and only fail from neck splits by minimum resizing and below max pressures.

Below shows the rear of the case with minimum head clearance when fired and "NOT" stretching and thinning in the base area.

Bottom line, do not push the shoulder of the case back excessively when full length resizing and keep your chamber pressure below maximum and your cases will last much longer.

Can't get any better than this for an explanation!My Sako in .300 WM does this on occasion.Time for new brass.

 

[Pyd]

A new clue perhaps?
I just took all the reloads I made (and shot once) out of the tumbler, almost all of them have a shiny ring just below where my last case fractured. The rest of the brass of about 25 that I did at the same time as the fractured one look great with the exception of that shiny ring. I ran a paperclip down as recommended and do not feel anything obvious.
Now I am wondering if I messed something up during the sizing process, I followed instructions to the letter. Is that ring significant, or an indicator of some form?
Almost looks like where the shell stopped on its trip up the sizing die, except my unloaded brass I did at the same time does not have that rim. These shoed up only on brass I have worked by myself, and fired.
Is this another indicator?

 

[Spawn-Inc]

That's why and where the case separates, but those look good for more reloads.

 

[cosmic]

You've been having a real go over the last month. First, cases were not sized enough, then perhaps too much.... The shiney ring is where the junction of the solid base meets the case wall - very typical, and not a problem. Put your current brass aside - tired brass causes headaches. Buy some new brass- don't bother resizing before using, despite what the pundits say - your resizing skills are lacking at this point. You don't need to buy expensive brass - its not worth it for you.
Learn to resize properly - set your die at the appropriate turn as per the die instructions. Check the case for fit, etc. Then learn to partially resize by adjusting the die further and checking the case.

 

[Pyd]

Thanks.
I have about 50 empty cases, all from the same place. It is only the ones that I loaded (and shot) that show this.
Going to head to the father in laws and have him make me a tool to measure exact wall thickness, I am perplexed, again.

 

[Pyd]

You've been having a real go over the last month. First, cases were not sized enough, then perhaps too much.... The shiney ring is where the junction of the solid base meets the case wall - very typical, and not a problem. Put your current brass aside - tired brass causes headaches. Buy some new brass- don't bother resizing before using, despite what the pundits say - your resizing skills are lacking at this point. You don't need to buy expensive brass - its not worth it for you.
Learn to resize properly - set your die at the appropriate turn as per the die instructions. Check the case for fit, etc. Then learn to partially resize by adjusting the die further and checking the case.

Yep, resizing skills are lacking, without doubt. I did follow the directions with my dies, right to the letter.
This has been a very steep learning curve, from never seeing a press in my life to diving right in. They feed, shoot (very well too), and now this little stuff is raising questions for me.
I regret resizing in the first place, but the deed is done.

 

[bigedp51]

New brass it is.
This rifle came with about 10 boxes of reloads, each box has the load data written on it.
After I fired a box or two I decided to reload, cleaned the brass, set my die to do a full length resize without a crimp, and started.
Looking back, the resizing process required a lot of effort, it led me to believe the cases were only being neck sized before I got them, I could be wrong.
A year after getting the gun I ended up with the original dies the owner used with the gun, RCBS.
I thought I had read everything I could to get started safely, this head clearance is not a term I have encountered. It makes me wonder.. After inserting the primers I set the cases on a plate of glass, some sit flush, others wobble as though the primer is not seated fully. I took great care cleaning primer pockets, and during the seating.
Looks like new Norma brass can be had for a buck a piece, but I need to get a better grasp on the "head clearance" topic, as well as what is meant by "bumping the shoulder", I get the concept, but not so much how I can control it with precision. Otherwise I will just wreck the new brass too.
I have some new words to run through Google, so thanks. That video explanation of head clearance was pretty awesome as well.

Pyd

Below is a military drawing for the 7.62 cartridge and chamber, manufactured cartridge headspace length is written as 1.634 -.006 meaning the case length is to be between 1.628 min and 1.634 max.

The rifles chamber headspace is to be 1.6355 min and 1.5405 max, as you can see from this your reloading die has some "wiggle room" for up and down adjustment for controlling head clearance.

You can also see the primer is to be .008 below flush when seated.

A military chamber is longer in headspace and larger in diameter than its civilian counterpart and when setting up your dies in most cases the die will not contact the shell holder when adjusted for the correct amount of shoulder bump.

Below is a exaggerated illustration of a fired case being resized, when you adjust the resizing die as per the instructions the shoulder of the case is pushed back to the green dotted line. To be a custom fit to "YOUR RIFLE" the die should be adjusted just a few thousandths below the red dotted line. On a bolt action rifle you push the shoulder of the case back .001 to .002 below the red dotted line and for a semiauto rifle it is .003 to .004. The further down you adjust the die from the red dotted line the more room the case has to stretch when fired. By keeping your resizing to minimum as written above the brass will stretch and then spring back when fired and not cause case head separations.

What is also important to remember is we live in a plus and minus manufacturing world so no two chambers and reloading dies are the same. I have a Lee full length .223 die that squeezes the cases smaller in diameter than my RCBS small base die set and pushes the shoulder of the case back .009 further than the RCBS die.

So just remember this, the instructions that come with your dies are to make sure the resized case will fit any rifles chamber. And all you have to do is adjust the die up and down for a custom fit for "YOUR" chamber and you will make your cases last "MUCH" longer.