Case head separation question

[pdhntr]

I will try to make the background as brief as possible.

I have been reloading for over 40 years and have recently built a 6br but have never been into loading for competition. The rifle is a 700 that I trued and fitted a Krieger barrel. I chambered using a reamer from Kiff and checked the headspace again tonight and it was .001 as I had chambered it.

I researched many posts on this site and many recommended using the Harrell's full length dies to resize. So I fired cases and sent them it to Harrells and they sent me a die. The die is marked B15.

I was shooting today and a Lapua case that I have fired 5 times and resize with the Harrells die had a case head separation.

My question is, (as I am still quite a novice at this stuff) is the Harrell die to be used EVERY time to resize the case or just when the case starts to become hard to chamber.

This post is not, and I repeat, NOT a judgement of Harrell's dies. They are tools to be used to perform a certain function, and I believe the operator may not know what he is doing.

Any help is appreciated.

Jim

 

[Eddie Harren]

You should have received a small brass colored "bump gauge" with the Harrell's die. If you use it to measure your fired, unsized case (taking care not to measure the primer protrusion) you can set your die to only bump the shoulder .001-.002" when sizing. Measure some fired cases and then size them and re-measure.

 

[Preacher]

The die should really be used each time you size the case..
It seems like your sizing them to much...
Do what Doc said...

 

[hogpatrol]

Are you using a neck bushing in the die?

 

[fdshuster]

Jim: If I had to guess, I would say you either had one defective case or you are oversizing the brass/ pushing the shoulders back too much.

I have Lapua 6BR brass that has been loaded over 40 times ( I keep a count on # of reloads) & have never had case head seperation in all of the BR & ppc Lapua brass.

With a new chambering, I hand punch out the primer, clean the case, then take a measurement for headspace length using the Stoney Point O.A.L. gauge. This dimension is recorded in that rifles log book & the Redding FL Type S neck bushing die is adjusted so that with each sizing, the shoulder is pushed back between .001" and .002". When I close the bolt on a loaded round I can feel just a little resistance, telling me the case is locked up in the chamber front to rear.

Case's seldom need to be trimmed, and when they do, it's only a few thousandths in length that is trimmed off.

Did the case that failed have to be trimmed during it's useful life? One clue that the case's are being oversized is the need to trim their length's, usually after every firing.

 

[pdhntr]

You should have received a small brass colored "bump gauge" with the Harrell's die. If you use it to measure your fired, unsized case (taking care not to measure the primer protrusion) you can set your die to only bump the shoulder .001-.002" when sizing. Measure some fired cases and then size them and re-measure.

Nothing was shipped with the die. I have no clue what a bump gauge is.

I am assuming it fits over the neck and sits on the shoulder somehow.

I could make one with the reamer and a barrel stub maybe.

Thanks.

Stop the presses......I just went out to the shop and looked through the little bag of stuff in the die box.

Guess what I found........a little brass colored "thingy" that I am guessing is to be used with the dies.

I my defence, there are no instructions with the dies, so I had no clue what it was to be used for.

The learning curve is pretty steep on some of this stuff.

Jim

 

[pdhntr]

Are you using a neck bushing in the die?

Yes. .267

Jim

 

[pdhntr]

Jim: If I had to guess, I would say you either had one defective case or you are oversizing the brass/ pushing the shoulders back too much.

I have Lapua 6BR brass that has been loaded over 40 times ( I keep a count on # of reloads) & have never had case head seperation in all of the BR & ppc Lapua brass.

With a new chambering, I hand punch out the primer, clean the case, then take a measurement for headspace length using the Stoney Point O.A.L. gauge. This dimension is recorded in that rifles log book & the Redding FL Type S neck bushing die is adjusted so that with each sizing, the shoulder is pushed back between .001" and .002". When I close the bolt on a loaded round I can feel just a little resistance, telling me the case is locked up in the chamber front to rear.

OK, so this is where I am lost again. What do you do to the cases that are fired and don't need sizing other than neck sizing? I can fire a case 3 or 4 times and it chambers just fine with no apparent feedback in the bolt handle. (I think this is where I may have made a mistake)

Case's seldom need to be trimmed, and when they do, it's only a few thousandths in length that is trimmed off.

Did the case that failed have to be trimmed during it's useful life? One clue that the case's are being oversized is the need to trim their length's, usually after every firing.

They were growing.

I think I understand what I did wrong, but see my question above.

Thanks.

Jim

 

[hogpatrol]

Jim, Some full length resize every time, some just neck size. Here's what I did. If you have a shell (once-fired or multiple times fired, unloaded, neck sized only and primer removed) that is hard to close the bolt on, check the length with the gauge supplied with your Harrels die. Then check one that closes without much resistance. Compare the two dimensions and adjust the die accordingly. There may be other methods and preferences but this works for me.

 

[pdhntr]

Jim, Some full length resize every time, some just neck size. Here's what I did. If you have a shell (once-fired or multiple times fired, unloaded, neck sized only and primer removed) that is hard to close the bolt on, check the length with the gauge supplied with your Harrels die. Then check one that closes without much resistance. Compare the two dimensions and adjust the die accordingly. There may be other methods and preferences but this works for me.

So now that I have the die set to just resize this case only the amount needed, do I use the Harrells die for all the cases each time I fire them? Or just keep firing (and neck sizing) until they give resistance and then use the Harrells?

Thanks again.

Jim

 

[fdshuster]

Jim: "with no apparent feedback in the bolt handle", got my attention. Case's that have been fired "4 or 5 times" certainly should be hard to chamber, if for no other reason than the case head ( shown on one of my PTG reamer drawings as being .470" dia.) would have expanded after that many firings if neck sizing only.

I'm guessing you may be oversizing the brass and do not realize it.

Have you taken a headspace measurement of a fired case, as it came out of the chamber?

I just sized 40 of my 30BR case's that I fired yesterday morning, knocked out the primers, cleaned the case(s) & measured the headspace lengths at a very uniform 1.155". Ran them into the Redding FL sizer, measured them again and they are now 1.154". I am able to chamber them with just a little resistance on the bolt.

If you are oversizing, pushing the shoulders back too much, the result would be "no apparent feedback in the bolt handle". How do the other case's look? Any sign of the beginnings of the bright shiney ring around the case head indicating a future seperation failure?

It would be strange for just one case to fail the reason I said it may have been a defective case. On the other hand if you are oversizing, they will all fail within the next few loadings.

 

[CanusLatransSnpr]

I'm of the assumption that this rifle is intended for competition? If so, then it would be in your best interest to full length size the brass each time. When sizing, size them the way that fdshuster explained. Just bump the shoulders back .001-.002". That is all that is needed. When this is done, it serves two purposes. First is so you have consistently sized brass across the board which would lend itself to having like pressure characteristics from shot to shot. Thus diminishing any chances of variation. The second purpose of fl sizing every time is so the rifle isn't disturbed much while cradled in the bags, and the rest, so you can return to battery more quickly and efficiently as to shoot the same condition!

Mike

 

[BoydAllen]

Jim,
Take a case that has been fired till tight, knock out the primer, slip the bump gauge over the neck, with the square end up, and making sure that the end of the neck is below the end of the gauge, use your calipers to measure from the end of the gauge to the head of the case. Write this measurement down. Now, take a case that needs sizing, and without the neck bushning in place, adjust the die so that the case measures .001 less than the first case, with the gauge and calipers, then you can put the bushing back in the die and run the case one more time, to size the neck. After you have done this, compare the diameter of the sized case at its largest diameter above the extractor groove, to the diameter, measured in the same place, of the first case (the one that is tight). It should be .0005 to .001 smaller. Then try the case in your rifle. It should chamber with minimal resistance, but not zero. As you continue to shoot a given set of cases in rotation, so that they all are fired and FL sized the same number of times, the cases will work harden, and have more spring back, this will require resetting your die slightly, to maintain the same bump. Be sure to check case length from time to time, and if you are shooting long bullets and your throat length is such that bullets' shanks are in the bottom of the neck, right at the shoulder, you should check for a constriction in this area, commonly called a doughnut. which should be removed so that it does not cause a clearance problem with loaded rounds in this area of the chamber. That ought do for now.

PS Case head separations are pretty much always due to case shoulders being pushed back too much repeatedly when cases are FL sized.

 

[pdhntr]

Jim: "with no apparent feedback in the bolt handle", got my attention. Case's that have been fired "4 or 5 times" certainly should be hard to chamber, if for no other reason than the case head ( shown on one of my PTG reamer drawings as being .470" dia.) would have expanded after that many firings if neck sizing only.

I'm guessing you may be oversizing the brass and do not realize it.

After the CHS yesterday I took three cases and shot them three times, only neck sizing them. Two of the cases were fired once and could have (probably) been full length resized after the first firing. One of the cases was new. The new case fired three times gives some pretty good feedback in the bolt handle, but not to the point of click. The other two give very little feedback.

This would seem to support your guess.

Have you taken a headspace measurement of a fired case, as it came out of the chamber?

I measured the three cases just now using Harrells thingy and came up with 1.567 for all three. The tighter one was actually 1.567 plus a little, I am guessing .0003 or .0004.

Is that how you take "headspace measurement" ? I really am not sure.

I just sized 40 of my 30BR case's that I fired yesterday morning, knocked out the primers, cleaned the case(s) & measured the headspace lengths at a very uniform 1.155". Ran them into the Redding FL sizer, measured them again and they are now 1.154". I am able to chamber them with just a little resistance on the bolt.

I can reproduce that process now. I understand.

If you are oversizing, pushing the shoulders back too much, the result would be "no apparent feedback in the bolt handle". How do the other case's look? Any sign of the beginnings of the bright shiney ring around the case head indicating a future seperation failure?

It would be strange for just one case to fail the reason I said it may have been a defective case. On the other hand if you are oversizing, they will all fail within the next few loadings.

I will have to look at them carefully. I am not a stranger to CHS. I know what to look for and how to check for it. However, this case let go much closer to the head than any other case I have seen. (Rem, Win....) Normally I see the "line" or tell tale sign much farther from the case head. This took me by surprise as I wasn't looking for it that close to the head.

I will get out my CHS tool and see if I can find it on others. I suspect there are more.

Thanks.

Jim

 

[pdhntr]

I'm of the assumption that this rifle is intended for competition? If so, then it would be in your best interest to full length size the brass each time. When sizing, size them the way that fdshuster explained. Just bump the shoulders back .001-.002". That is all that is needed. When this is done, it serves two purposes. First is so you have consistently sized brass across the board which would lend itself to having like pressure characteristics from shot to shot. Thus diminishing any chances of variation. The second purpose of fl sizing every time is so the rifle isn't disturbed much while cradled in the bags, and the rest, so you can return to battery more quickly and efficiently as to shoot the same condition!

Mike

Thanks Mike.

That answers my question.

Jim

 

[pdhntr]

Jim,
Take a case that has been fired till tight, knock out the primer, slip the bump gauge over the neck, with the square end up, and making sure that the end of the neck is below the end of the gauge, use your calipers to measure from the end of the gauge to the head of the case. Write this measurement down. Now, take a case that needs sizing, and without the neck bushning in place, adjust the die so that the case measures .001 less than the first case, with the gauge and calipers, then you can put the bushing back in the die and run the case one more time, to size the neck. After you have done this, compare the diameter of the sized case at its largest diameter above the extractor groove, to the diameter, measured in the same place, of the first case (the one that is tight). It should be .0005 to .001 smaller. Then try the case in your rifle. It should chamber with minimal resistance, but not zero. As you continue to shoot a given set of cases in rotation, so that they all are fired and FL sized the same number of times, the cases will work harden, and have more spring back, this will require resetting your die slightly, to maintain the same bump. Be sure to check case length from time to time, and if you are shooting long bullets and your throat length is such that bullets' shanks are in the bottom of the neck, right at the shoulder, you should check for a constriction in this area, commonly called a doughnut. which should be removed so that it does not cause a clearance problem with loaded rounds in this area of the chamber. That ought do for now.

PS Case head separations are pretty much always due to case shoulders being pushed back too much repeatedly when cases are FL sized.

Thanks Boyd. Very good instructions.

The reamer I got just so happens to place the end of the bearing surface of the 105 Bergers just above the neck/shoulder junction.

Luckily, I don't have to worry about the donut on this one.

Jim

 

[pdhntr]

Well, I just took one of the cases that was full length sized and measured and it is 1.555.

That means I was pushing the shoulder back over .010 each time I full length resized!

I simply didn't understand the Harrells die. I thought the reason I sent three cases that were fired 3 to 4 times was so I would get a die that would "bump" the shoulder back one or two thousandths.

I should have "talked" with you guys first before screwing up a bunch of nice brass.

The "education" continues.

Thanks to all again, I think I am on the right track now.

Jim

 

[BoydAllen]

Jim....buddy,
The purpose of sending in the cases is NOT to get the right shoulder bump. In fact, I don't know where you got that idea. It is to get the right amount of sizing of the diameter of the body of the case, especially near the head, just above the extractor groove. YOU have to set the bump with any die. Sorry if I am being to emphatic. It sounds as if we are finally getting somewhere. Did you read my instructions in my last post? They were very step by step, except for not mentioning that you should lube the body of the case before doing any sizing. I figured that you know to do that.
Boyd

 

[pdhntr]

Jim....buddy,
The purpose of sending in the cases is NOT to get the right shoulder bump. In fact, I don't know where you got that idea. It is to get the right amount of sizing of the diameter of the body of the case, especially near the head, just above the extractor groove. YOU have to set the bump with any die. Sorry if I am being to emphatic. It sounds as if we are finally getting somewhere. Did you read my instructions in my last post? They were very step by step, except for not mentioning that you should lube the body of the case before doing any sizing. I figured that you know to do that.
Boyd

Boyd, I don't know where I got that idea. It probably came from reading posts from this site (almost the only one I go to anymore) by guys that are experienced and experts that don't have to explain the basics of certain dies, and how they are used, as they are addressing other guys that are experts. They recommended Harrells dies for full length resizing. So I assumed that a full length die is to be used as I have used all my other ones, screwed down all the way. Normally, factory full length dies do not do a good job of bumping the shoulder as they also resize the base too much. So that is why there are shoulder bump dies.

I didn't know that is why you ship fired cases to Harrells to get the right sizing at the base. I understand now. Also, there were not any instructions with the Harrells die. I just plain screwed up.

From someone that is an experienced reloader and has been doing it for many years very successfully, for hunting and varmint applications, this reloading for competition is a whole 'nother world.

By the way, I set up the die as instructed and bumped the shoulder back .001 (on a case that was giving resistance.) The case chambers without resistance and the base is, indeed, about .00075 smaller than before.

I also cut open several of my 4 and 5 times fired cases, and found only a very slight thinning above the web. I believe the CHS was a combination of my ignorance and maybe a thin case (at the web) on that particular case. Good news.

Thanks to all again. You have been very helpful.

Jim

 

[BoydAllen]

Jim,
I am glad that you understand. Now...get one of those Hornady kits that use different attachments, and has an adapter for your calipers, and check your other calibers. If you have been running the dies down to the shell holder, my money is on your having set all of those shoulders back too far. This is not a just a benchrest thing. I remember years ago, before I knew anything about any of this, listening to fellows speculate as to why their belted magnum cases did not last for very many firings. They had no clue (neither did I), and wrote it off to magnum pressure levels. Any reloading of bottle necked cartridges, rimless, rimmed, or belted, should should including setting the shoulder bump, by measuring, any time that FL, body, or shoulder bump sizing is done.
Boyd