I had a case separate 1/4 inch above the belt leaving the body and neck in the chamber. Caliber was a .375 H&H magnum and the case had been fired 4 times. I have 99 other brass and am now concerned that I can no longer use the other brass safely. I inspect each brass externally before reloading and see no defects in the remaining brass.

What happened?

Can I use the othe brass safely?

Thanks.

Do an internal inspection...

Case life of most magnum brass sucks. As Ric suggests, check internally, either with strong light or with a bent wire...moving it along inside the case body...feeling for a ring where the case is moving toward separation.

You may wish to mark the rest of the brass with some identifying mark in case it can get mixed up with better brass. I would say the rest of the cases are suspect.

Just one of the joys of magnum cases.

You are alternately pushing the shoulder back with the size die and blowing it back out when firing. It will not leak gas or blow up your rifle when the head seperates. You can use a brush larger than the size of the inside of the case to remove the broken off front. Push it in the case and pull it out.

welcome to magnum brass!- Neck size it only after the first firing and chuck all your brass after 7-8 firings. Don't FL size until the brass won't chamber easily again. When you FL size, as someone said you are pushing the shoulder back, and then blowing it out again. That's why your getting the case separations. You probably have wrecked your other 99 cases and I would not trust them anyway. By the way repeated case separations will eventually gas cut your chamber, so it is not a good practice to do this repeatedly.-Rob

I agree that case head separations can be dangerous and destructive. Had one happen in a .30-06 using brass of indeterminate origin(despite the urban legends to the contrary, rimless cases are just as subject to case head separations as belted, rimmed, or rebated) which blew the extractor off of a Sako, although no damage was suffered by the shooter.

If all of your 99 other cases have been full-length sized 3 or 4 times, they are ready for the bone yard (as would be .30-06 or .220 Swift or any other case).

The only reason that belted cases have a worse reputation for case head separations is that many reloaders believe that (1) they will headspace adequately on the belt and (2) that for some reason they must be full length sized. The fact that many manufacturers also hog out the chambers of belted calibers rather sloppily only adds to the problem. Treat belted, bottleneck cases just like you would any other bottleneck case by resizing only enough to allow reasonably easy reentry into the chamber. Make them headspace on the shoulder as any proper bottleneck should. Because of their generally heavier web area, they will last as long or longer than rimless.

Ron L,
Usually the first sign of pending case seperation is a bright ring around the case at the point where the seperation will take place. If your other cases have this ring, junk them! The other postings are right about the shoulder of the case having been moved to far back during sizing. It doesn't take much too create this situation. The smaller the error the longer the case will last. A large error wil cause a new case to fail and seperate or damage your rifle.

If you're curious about it, these are the mechanics of what happens. When the rifle is fired with a short case in it, the firing pin drives the case forward in the chamber as far as it will go. As the powder burns, the gases cause the case to expand. The thinnest part of the case expands first. The thinnest part of a case is the neck. The thickest part of the case is the web, the part just in front of the belt. This is the last part of the case to expand. The expandtion starts with the neck and moves towards the rim. As the expanding case comes into contact with the chamber, increasing pressure prevent the rearward movement of the front of the case. The face of the case, due to its being short, is not supported by the bolt face. With the front half of the case held in place, the rear of the case is forced rearward against the bolt face. this results in the case being streched. At the point where the cases does strech the case becomes thin. The seperation occurs at the thinnest part of the brass. I suggest that you ignore the belt and adjust your sizing die as if the case were a rimless design, or necksize only. I hope that this is of some help. Good luck. Let us know how it works out for you.

Gentlemen

Here is what I did before working all those cases.

I took the firing pin out of my .375 bolt. I then adjusted the sizing of my brass so that when closing the bolt, very little resistance was felt. I assumed that this would be neck sizing and pushing back the shoulder slightly.

To adjust the die to do this , I went through the following process.

Adjusted the body of my die down until it met the ram which was in an up position and then went 1/8 of a turn more before locking down the ring.

Adjusted the stem of my die down slowly until I could see that the upper 1/2 neck of my brass was being resized.

Tried the brass in the gun but the bolt did not close easily.

Brought the stem of my die down 1/4 turn at a time and checked the brass in the gun each time.

Eventually the bolt of my gun closed with little resistance. Upon examining the brass, I could now see that that the entire neck had been resized.

A problem was then encountered where the pin on the stem was not long enough to kick the spent primer out of the case.

I had to lower then stem 1 full turn more to get the spent primer to be pushed out of the case by the pin.

Upon checking the brass again in the gun, the bolt closed with very little resistance.

After 4 firings, the case separated from the base of the brass just above the belt.

What should I have done different?

Thanks for the advice.

On all of my dies the sizing is controled by how far into the press you screw the die, the adjustable stem only controles the expander/decapper.

"To adjust the die to do this , I went through the following process.

Adjusted the body of my die down until it met the ram which was in an up position and then went 1/8 of a turn more before locking down the ring."

What I do is: Starting with a piece of fired brass that has had the neck 'smoked' (or colored with a felt marker), and the die 1/4 inch away from the top of the ram. Bring the die body down 1/4 turn (or less) at a time until you just touch the shoulder (you don't want to push the shoulder back more than .001-.002). The 'smoked' neck will let you see your progress. Lock the die in at this point. Now adjust the decapping stem to push out the primer (if it's not already). As your getting close to the final settings you should check to make sure that it chambers properly (slightly easier than a fired case, slightly harder than a factory).
Touching the ram is a basic, general, fits all way of doing it, however what I'm suggesting is going to adjust the die to match your chamber.

Resizing too much is one thing, but I had a batch or Norma 7mag brass that was about .1" short for the chamber, when new. If that brass had been fired, as shipped, it would have had instant problems, even with that one shot.

Instead, I ran it over an oversized expander (created a double shoulder), neck sized the upper 3/4's of the neck, loaded and fired. No sign of separation after 5 loadings, whatsoever.

With belts, the comination of short brass, large chambers and small dies can be a total disaster. With proper brass, tight chambers and the right size dies, they work great. FWIW, Dutch.

What brand of brass do you have? Some brass is softer and flows more than others. I had a head seperation with regular 8mm with Seller & Belloit brass. My RP brass had the same number of cycles and pressure loads had no thinning at the head the S&B all had thinning and is now history. JB

Gentlemen

The brass that separated is Winchester.

I loaded up some nickle R/P earlier this week and after 2 firings I noticed a line developing in the nickle finish just above the belt about in the same position that the other Winchester case separated.

I brought out my micrometer today and did some measurements as follows:

base shoulder neck
diameter diameter diameter
Book Specs .513 .448 .402
Factory Federal Safari .507 .448 .396
new unsized Win brass .508 .448 .394
resized brass .512 .447 .394
fired brass .511 .453 .403

This is a Redding die. The specs on the resize brass would seem to suggest to me that the chamber cut of the die is correct.

I trim the cases to 2.840 but after one firing and resizing they grow to 2.848 in length.

I am using 68 grains of Reloader 15 with no signs of pressure.

I am gaining .006 in shoulder diameter after firing the round. I then push the shoulder back by .006 when I resize. Is the chamber of my rifle cut too large at the level of the shoulder?

I tried backing my die out to only partially resize but now there is 1/4 of an inch between the bottom of the die and the top of the ram with my shoulder still measuring .447 and I am now only resizing about 1/2 the length of the neck.

I need some help.

Opinions would be greatly appreciated.

[ 08-03-2002, 09:00: Message edited by: Ron L ]

It is normal to have a chamber that allows significant forward expansion of the case shoulder. This is no rpoblem with factory ammunition which is fired only once, but is a problem for the reloader. To solve the problem, you have to back the die out of the press far enough so that the shoulder is not set back during sizing.

Smoking the case is the tradition approach to find the right die setting, but I just do it by feel. Starting with the sizing die well away from the shell holder, move the die down an eighth of a turn at a time until the cases chamber with only slight resistance -- no more than slightly easier than a fired case. If you have more than one rifle of the same caliber and want to shoot the same ammo in them, you will need to check that sized cases will fit in all the chambers. Then lock the die. Once you get the right setting, the cases will last longer and the ammo will be more accurate.

Gentleman

I did try backing the die up but I ran out of downward travel on the stem of the die. With the stem turned in as far as possible on the die, I was only able to resize 1/2 of the neck of the case and the shoulder was still being pushed back by .006. I now have 3/8 inch space between the bottom of the die and the top of the ram on the press. If I keep backing the die up, I will be resizing less than 1/2 of the neck on the case.

What am I doing wrong?

[ 08-03-2002, 16:14: Message edited by: Ron L ]

Ron:

I do not understand what is happening. Wish I could see it.

The stem in my dies only moves the neck expander ball. It has nothing to do with case sizing.

You cannot be only sizing half the neck and still moving the shoulder. The shoulder of the die does not touch the shoulder of the case until you are sizing the entire neck. How are you determining that the shoulder is being set back?

Most good manuals have a section on this subject with pictures that may help.

Sorry I can't be more help. It is difficult to visualize what is happening.

I am measuring the diameter of shoulder with a micrometer. Once the case if fired it measures .453. After I resize it, I get a measurement of .447. Factory specs show the diameter should measure .448.

I can visually see resizing of the neck is now only going 1/2 of the way down to the shoulder. The neck diameter measurement goes from .403 down to .394 after resizing.

Maybe I do not understand what you mean bu "pushing back the shoulder". How should I be measuring this to see if I am "pushing it back too far"?

Thanks for your interest in my problem.

Question, Pushing the shoulder back or reducing it's diameter? There is a difference.
You didn't give us the base to shoulder or base to bottom of neck dimentions.
Book dim. for base to shoulder is 2.412 and for the base to bottom of neck dim it's 2.498. I'd expect to see those numbers being higher (longer) in your fired brass (and within .000 and .002 of the fired brass with your sized brass).
Way's to eliminate the diameter growth? 1) A true neck sizing die. (DS you still need to FL size now and then) 2) Have the chamber recut to a tighter tolerance. (DS expensive and might not cure the problem) 3) Have Redding recut the die to match the chamber (DS die will only be right for that rifle). Me I'd opt for #3 first or #1 second.

I use the Redding Instant inicator tool to determine where to lock down my FL dies in the press to acheive a .001 push back of the should. In the process of setting up my dies for 4 belted mags, 7mm Rem, 7mm STW, 300 Win, and 270 Wby, I made some observations. As a note, all of these rifles have custom barrels with minimum chambers with the exception of the 7mm Rem.

For those not familiar with the Redding tool, it uses a dial indicator to measure the the position of the shoulder with respect to the shoulder of a chamber 'go' guage or another case.

What I observed was true for all of the calibers mentioned. When comparing fired cases to the go guage, they were nearly identical, the cartriges in the custom barrels were right on and the factory barrel fired cartridges measures about .001 or .002 longer.

After getting my dies properly adjusted, I thought it would be interesting to compare the fired (and unresized cases) to new brass. I was amazed. All four of the above cartirges measured a full .015 shorter than the fired case and thus, the chamber. I have made this same comparison on Norma, Wby, Win, and Rem brass and all are about the same. Since the belted mags headspace on the belt, not the shoulder, there is no problem with the initial firing. However, for me, this explains the shortened life of belted mag brass compared to non-belted brass. That first firing really stretches the cases. once I started adjusting my FL dies this was, my case life has improved dramatically, nearly as good as neck sizing only.

I did a similar comparison with 243, 223, and 30-06 and found the difference between new and fired brass to only be from .003 to .005. The 243 was the .003, but it is a custom barrel with w minimum chamber, the others are factory.

Ron L, I wanted to show you a tool I made up to check all my brass before loading. I do not want another head separation. I found brass with this device that did not show a bright ring that did have thinning. I run the brass over the dental pick and watch the meter, if the needle goes backwards the brass is retired. The paper clip will feel a hollow. The meter will point up a weak spot the paper clip won�t feel.

http://pic5.picturetrail.com:80/VOL81/618767/974652/12070912.jpg

As far as setting up your die. The way I do it is I set the expander ball in the normal setting for a full length resize. I run the die into the press so it bottoms on the shell
holder and cams over. Then I back the die out the thickness of a Nickel and make my small adjustments from there. I have not had to soot the brass as I can see how far down the neck I want to size. I usually stop short of the shoulder. At that setting the body of the shell is somewhat sized but the shoulder is not bumped back. My last remark is to your shell holder. I assume yours are standard and you know they are not the RCBS shell
holders that are made thinner for the purpose of bumping the shoulder.

Best of luck, I forgot to tell you that you can order the meter pictured from www.homier.com for $7 +SH. JB

Ron L...

You haven't mentioned what rifle you are shooting... I'm just curious.

I shoot several belted magnums, including the .375 H&H, and the .375 H&H is my favorite of the bunch.

It is a pussy cat cartridge to load, with no bad manors.

I think you are using your micrometer too much and worring about the numbers too much... there is a tremendous difference between the numbers in the book, and the measurements you will get from your own fired cases... don't worry about it.

When the case is fired in YOUR chamber, the numbers are now YOUR measurements.

The .375 H&H has such a tiny shoulder that you should NEVER full size the cases... you need all the shoulder you have to hold headspace... it DOES headspace on the shoulder! Even on the first shot!

Current belted chambers are not cut to headspace on the belt.

Please answer these questions...

When you fire a round, can you rechamber the fired case:

NO? you have a problem, take it to a gunsmith, or send it back to the maker.

YES... then you have no problems.

You should buy a quality "Necksize" die from a good maker (Redding, RCBS, etc), and then hide the FL die up in the attic, where you will never find it again.

Set the necksizer die 1 turn above the ram head, so the last few milimeters of the neck are NOT sized... you will be fine!

95% of case problems (head space - head separations) in modern rifles, (belted, and nonbelted cases) come from improper use of FL dies.

The only purpose for an FL die, is to resize brass from other rifles, or for resizing brass from auto rifles.

CatShooter.

[ 08-03-2002, 21:12: Message edited by: CatShooter ]

Catshooter

I can close the bolt on a fired round but there is some pressure when I do this. Do I have a problem with the cut of my chamber?

Ron L

Please tell us what rifle it is??

If there is only a light resistance when closing the bolt, but it doesn't require "force" to close, this is a good thing (so says Martha Stewart) .

The reason is... this resistance will help hold the case from being pushed forward from the firing pin, and primer thrust... the ideal situation is that the case is held back against the bolt face firmly after the primer goes off... then there is no posibility of stretch at all.

I probably have 10 firings on my .375 H&H, and my .300WM cases, and no sign of any stretch... I Don't own FL sizers for either caliber... only neck sizers, and seaters.

CatShooter.

[ 08-03-2002, 22:27: Message edited by: CatShooter ]

Ron:

Now I understand. It is not the diameter of the shoulder, but the length of the case from base to shoulder that is the issue and causes the headspace problem. You want to run your sizing die down into the press until the neck is sized fully, but the shoulder is not set back any more than necessary to chamber the case. If your cases chamber OK without moving the shoulder at all, that is best. After several firings, you may find that a slight setback of the shoulder is necessary to chamber the case, but the less the better. This will solve the case separation problem.

KLN...

The problem with using a FL die to "partially" size a belted case is this:

Belted FL dies are cut differently that the FL dies for non-belted cases.

The diameter of the edge, just before the belt is fairly small, and will most often, push a little brass in front of it, if it has not been properly rounded... this "little bit of brass" builds up and after a few reloads, it will really interfere with chambering.

Some yahoo has invented a special die to get rid of this enlargment of the base. It's only about $80, and a pain in the ass to use.

If you wanna neck-size, then get a Neck-size die, and don't crap around... especially with belted cases.

Life can be so easy... why work overtime to make it so hard?

CatShooter.

[ 08-03-2002, 22:24: Message edited by: CatShooter ]

If there is only a light resistance, but it doesn't hinder your movement, this is a good thing (so says Martha Stewart).

The reason is that this resistance will help hold the case from being pushed forward from the firng pin, and primer thrust... the ideal situation is that the case is held back against the bolt face after the primer goes off... then there is no posibility of stretch at all.

I probably have 10 firings on my .375 H&H, and my .300WM cases, and no sigh of any stretch... I Don't own FL sizers for either caliber... only neck sizers, and seaters.

CatShooter.

[ 08-03-2002, 22:49: Message edited by: CatShooter ]

The rifle is a stainless Winchester Model 70, the new controlled round feed action.

Who manufactures a neck sizing die for a .375 H&H magnum and where can I buy one mail-order?

Thanks for all the advice guys.

Redding and RCBS make them. You can buy it from Cabela's, Midway, and other stores. Never had a problem with case head separation