Case bulge...Help

[oliverstacy]

I have a question about incipient case head separation, concerning 375 Winchester rounds.  Reading some on this over the years and have never seen it first hand so here goes.  I was cleaning some 1 and twice fired brass and notice a bulge on some of the cases just forward of the web area.  Some were not bad and resized out.  Some upon resizing showed a bright line on half the case that can be felt with your finger nail.  These I have a feeling are going bad and should be scrapped.  Some have a bright narrow line all the way around the cartridge and again I’m assuming they’re also bad.  I was using this lot of brass for load development in my TC Encore 24” barrel.  

Some of the loads don’t show any signs of pressure either on the case or the primer and didn’t expand any.  I’m assuming I’ve reached a dangerous level and need to back it off some in the powder department (even though I was under the max or right at the max for all loads).  

Do I have a headspace problem?  Or is it too hot of a load.  I hope it’s not a headspace problem because this thing shoots amazing group at 100 yards.  We’re talking 1” to 1.25” 5 shot groups.  The best load was a grain under the max listed in Hornady’s manual.

Thanks for the help,

Josh

[Larry Gibson]

I have a question about incipient case head separation, concerning 375 Winchester rounds.  Reading some on this over the years and have never seen it first hand so here goes.  I was cleaning some 1 and twice fired brass and notice a bulge on some of the cases just forward of the web area.  Some were not bad and resized out.  Some upon resizing showed a bright line on have the case that can be felt with your finger nail.  These I have a feeling are going bad and should be scrapped.  Some have a bright narrow line all the way around the cartridge and again I’m assuming they’re also bad.  I was using this lot of brass for load development in my TC Encore 24” barrel.  

Some of the loads don’t show any signs of pressure either on the case or the primer and didn’t expand any.  I’m assuming I’ve reached a dangerous level and need to back it off some in the powder department (even though I was under the max or right at the max for all loads).  

Do I have a headspace problem?  Or is it too hot of a load.  I hope it’s not a headspace problem because this thing shoots amazing group at 100 yards.  We’re talking 1” to 1.25” 5 shot groups.  The best load was a grain under the max listed in Hornady’s manual.

Thanks for the help,

Josh

Not a headspace problem, it is normal expansion at the case web. This happens with loads above a certain pressure. Your loads are ok but you are sizing them to much. Constantly sizing them as in; "Some were not bad and resized out." will increase the likelyhood of a case head seperation. You might want to back the sizer out until it sizes the cases just enough to give .002"-.003" smaller inside neck diameter than your bullets. Doing this is called "partial resizing". This will not work the brass so much in the web and will also reduce case stretching and the need for trimming so often.  

Larry Gibson

[Questor]

You may want to try the "paper clip" test for incipient case head separation: Straighten a paper clip and bend a short L-shape into it. Sharpen the tip of the L. Reach down into the case with the bent wire to feel for a groove in where you think the separation is beginning. If there's a groove there, then you've got a problem. It's hard to believe that only two firings in such a low pressure cartridge would do this, but it's better to be safe than sorry.  I know that I get a bulge at the base of some cartridges because the sizing die only goes down so far, but what you describe seems like a sign to worry about.

[Siskiyou]

Questor's answer is right on.  It is hard to beat the old paper clip test.

[oliverstacy]

The bulge is almost always on one half of the brass, does this mean the chamber was cut wrong.  I couldn't find a paperclip last night to save my butt, I made one up at work today and I'm about to head home to see what I find.  

About the resizing issue.  I set it up like any other time I have in the past 12 years and I've never had a problem like this.  I place the ram all the way up and then screw the die down until it touches the shell holder.  Now that I think about it I did give it an extra 1/4" turn before I tightened the nut and screw.  I thougth this would be better for the brass because it would contact more of the case.  How did this hurt the case?  How would not sizing it as much change the outcome?  If the bulge is on the case and I resize the case and the die smooths them out and they don't show a shinny ring are they okay?

I'm going to try to post some pictures latter and see what you think about them.

Thanks again,

Josh

[Siskiyou]

If my loads are for the same rifle I do not go all the way down to the die.  I then test the cases in my rifle before proceeding with the rest of the reloading steps.  It has been a long time since I have looked at a .375 Winchester case.  If it has any shoulder you could be buckling the case a little.
How do the resized empty cases function in you firearm?

Dinner bell just went off.

[oliverstacy]

It is the fired rounds that have this problem.  All of the loaded rounds are as straight as they come.  I only noticed the bulges after I tumbled the brass and they were nice and shinny.  It was almost as if there was a very small shoulder at the base of the brass just in front of the web/primer pocket.  Some we very hard to see and upon sizing them you can't notice it at all.  Others had a very pronounced bulge and not after resizing have a bright line partially or all the way around the case.  You literally can feel it with your finger as a ridge like feel.

I just used a straightened paper clip and cannot feel a grove on the inside of the case.  From the looks of it, the sharp line on the outside of the case is exactly where the web of the brass is.  So I'll probably take the gun to a gunsmith and see what he thinks.

With the larger bulges, if I would have backed the die of a few thousands it would have been okay?  Is that what I'm sensing?

Please keep the ideas coming.  

Josh

[EsoxLucius]

This is common with straight-walled or slightly-tapered rimmed cartridges.  It is caused by the brass conforming to your rifle's chamber.  There are probably no case head separation issues, it is normal.  I would agree that if you do not have to full length size, don't.  You can either partially size or get a Lyman Neck Die and only size that portion of the case that will accept the bullet.  That, in conjunction with expanding with a Lyman 'M' Die, will go a long way in increasing the life of your brass.

[jgalar]

Take a case that you think looks really bad and cut it in half. If the head is starting to seperate it will be easy to see on the inside with the case cut.

[Steve P]

About the resizing issue.  I set it up like any other time I have in the past 12 years and I've never had a problem like this.  I place the ram all the way up and then screw the die down until it touches the shell holder.  Now that I think about it I did give it an extra 1/4" turn before I tightened the nut and screw.
Josh

Whoa!  Stop right there.  You have just described the initial starting point in adjusting the sizing die.  This will give you a starting point but is NOT the end result.  You still have to adjust your die to your brass and to your gun.  I trust you sized and trimmed all your brass when new?

For the encore, you only need to size the brass enough to get a firm closure in the action.  You want that rim against your action, not dropping into the barrel.  If the brass is overly sized, you have a few thousandths jump upon firing before the rim hits the action.  With a bullet near the lands, and seated deep in the case, the rim can only move backward to the action by stretching the brass.  

Take a fired brass and see how it fits in your encore.  Does it slide right in?  Firm closure of the action?  If so, you want to set that sizing die to just kiss the brass in the area where the bullet is seated.  No more.

Brass rim thickness is not always uniform.  Neither is the rebate in the barrel.  Dont size Encore or Contender brass on the rim.  Size all Encore and Conteder brass so you just get a firm closure of the action.  There are exceptions to this rule (22 hornet) but it works for most.

Steve