I seriously doubt this is case head separation but what do you guys think?

[gohring3006]

Is it more prominent to one side of the case?
The large chamber theory might be the issue. The case supported by the boltface and the chamber is bigger.

 

[jimbires]

Ok so just so I'm understanding... I need to expand the brass fully by firing and then set the die to only bump the should back .002?

Can't I take the brass I just fired a few days ago and slowly spin the die down to get to the point where I barely bump the shoulder back?

take that fired brass and neck size only for a couple more times to get the brass fully expanded .it will start to get tight to chamber . then set up your full length die to bump the shoulder about .002 .

 

[26Reload]

So...following along here...this problem is most likely brass flow vs chamber diameter....
So all new brass needs at least two fire forming's before
it can be considered viable as chamber fit....
In the two fire forming's the only thing needs checked is case lenght and trimmed if necessary to stay below brass oal....and resizing when brass won't allow bolt to reach lockdown....
I had a case separation once..7mm mag....bolt caught the bridge of the nose and plastic glass lenses....really lucky there...no noticeable body discoloration on brass...not hot loaded....
This thread is really good for info...thanks guys...

 

[timberelk]

So...following along here...this problem is most likely brass flow vs chamber diameter....
So all new brass needs at least two fire forming's before
it can be considered viable as chamber fit....
In the two fire forming's the only thing needs checked is case lenght and trimmed if necessary to stay below brass oal....and resizing when brass won't allow bolt to reach lockdown....
I had a case separation once..7mm mag....bolt caught the bridge of the nose and plastic glass lenses....really lucky there...no noticeable body discoloration on brass...not hot loaded....
This thread is really good for info...thanks guys...

I completely understand the reason behind fire forming the brass and only neck sizing but this gun will be for back country hunting where it will be subjected to rain, snow, dirt, mud, leafs, twigs, etc.

The round has to chamber 100% or as close to 100% as possible.

May I have head spacing issues?

What is the typical amount a bottle neck brass case should expand during each firing?

 

[J E Custom]

Bumping the shoulder Only increases the head space compounding the problem if it is case stretch in the web area. If it is just the chamber that is bigger, you can use normal loading practices.

It is normal for some case designs to grow in length 4 or 5 thousandths each time they are fired, But 10 thousandths is a bit much.

Hear is a link to some examples of case head separation. scroll down until you see the cases that have been sectioned and you can see what it looks like on the inside near the web.
https://www.google.com/search?q=cas...r=1.5#imgrc=ZBC3zU7zYsb-6M:&spf=1519320844481

J E CUSTOM

I will cut one case open and check mine out. Are you thinking I have head soar issues? How would I know if I have head space issues vs a large chamber?

Excessive head space occurs when the case is shorter than the chamber
by more than 1 or 2 thousandths allowing the case to move backwards against the bolt face and them move forward to the shoulder stretching the case more than the chambered head space (Normally .0005 to .0015). this condition is normal as long as the case does not stretch more than the existing head space.

When this happens the case will move back against the bolt face and remain there throughout the firing sequence, The rest of the case expands forward because sufficient pressure has not been reached for the case to expand outward (Bigger in diameter) allowing it to stretch in length. As pressure rises, the case expands and grips the chamber wall stopping it. From there on, pressure begins to compress the case walls causing it to thin in the neck shoulder more than the rest of the case. until it contacts the shoulder and stops.

If you have a good gunsmith close, have him head space your chamber and compare a fired case to the SAMME specifications.

J E CUSTOM

 

[MagMan]

By chance have the lugs been lapped lately?

 

[bigedp51]

timberelk

Measure a fired case at three points along the case body, then remeasure the case again after full length resizing and write it down. How much is the die reducing the case diameter.

I have a Lee .223 full length die that will reduce the case diameter more than my RCBS .223 small base die.

Again the more the die reduces the case diameter the longer it will be after sizing. And you are getting advice from reloaders that prefer neck sizing only.

Below is as close as I ever got to a total case head separation, and it happened on a .303 British Enfield rifle where the die did not match the chamber dimensions.

Below are .303 cases, from left to right, a new unfired case, a once fired case and a case fired three times. The rifle was within SAAMI headspace, meaning .002 more than minimum headspace. But because of thin rims these cases had .009 head clearance. And the cases expanded more in diameter because of the larger diameter military chamber.

Below these .308 cases were full length resized with the die adjusted per the instructions. Meaning the die was not adjusted for minimum shoulder bump of .001 to .002. And these cases were fired in a brand new Savage bolt action rifle.

Below my RCBS Case Mastering Gauge that can measure case wall thickness and any stretching and thinning of the case. Its a $100.00 bent paper clip that measures to .001 of an inch and also bullet runout.

Below this sectioned .303 British case stretched .009 on the first firing.

Bottom line, if you are only bumping the shoulder back .002 from its fired length you should not be having any case stretching in the base of the case.

 

[jimbires]

I'm " only " telling you to neck size " a couple of times " to get your brass fully expanded . then you will be full length resizing ,by bumping the shoulder .002 , for ever .

 

[bigedp51]

There is a big difference in how much the OAL is after sizing and where the case shoulder is.
None of us have the rifle and cases in our hands and the OP is even being told to take the rifle to a gunsmith and check the headspace.

SAAMI headspace on their chamber and cartridge drawings is listed as min and max. And there is .010 between the min and max tolerances. And GO and NO-GO gauges have .003 between them and are used to set up new rifles or re-barreled rifles.

Chambers and die vary in size and the OP might have a large chamber and a resizing die on the small side. Meaning this would explain why his OAL case length after resizing the case.

I'm 67 and have been reloading for over 47 years and have never just neck sized a case until it has resistance closing the bolt and then switch to full length resizing. Bottom line, keep it simple and bump the shoulder back .001 or .002 after measuring a fired case. The third time I neck sized a 30-06 case in a Remington 760 pump the case would not eject until the case cooled off a few minutes later. So what is gained by firing a case 2 or 3 times to find out when the bolt is hard to close.

So far the OP has been given some bad advice, a new case has been annealed and the case shoulder and neck are soft. And yes the case shoulder will spring from its fired size and a resized case shoulder will spring back from its resized location. And you are talking about a few thousandths of an inch and the OP is measuring the fired case and not guessing where the case shoulder is at.

Thousands of reloaders just use a Wilson type case gauge to measure the "resized" case and never have a problem. And the OP has a Hornady cartridge case headspace gauge and is measuring the "fired" case length and is more precise than a Wilson type gauge.

Now look at the chart below that I posted before, and read the chart at what point the case started to stretch. These cases did not start to stretch until the 7th firing, meaning the sizing die was a close match to the rifles chamber.

Bottom line the OP needs to do some more checking and measuring, but the OP doesn't need to start neck sizing or take the rifle to a gunsmith.

 

[MagMan]

"over 47 years and have never just neck sized a case until it has resistance closing the bolt and then switch to full length resizing."

The point was that you can neck size (to shoot multiple times) withought having to buy a neck sizing die.

Otherwise know as partial FL sizing.

To the point where FL sizing is necessary.

 

[timberelk]

I ended up contacting Legacy arms and they instructed me to speak with their gun smith. After a detailed conversation, he recommended I send him the rifle and he can check out the head space and as well the reason it is not shooting sub MOA with factory loads (it is shooting MOA with reloads) and he would ensure everything is cleaned/polished in the chamber.

I will be out a gun for a week or so but customer service seems to be top notch!

 

[Canhunter35]

Wouldn't excessive head space cause the primers to be pushed out?
Just wondering?
I thought that was a symptom of oversizing your cases

 

[bigedp51]

I have used a full length die to partially resize a case, and prefer to totally full length resize. The only cases I partially full length resize are .303 British cases because the die size and chamber size of the military rifles are far larger than the die.

Below German Salazar explains the benefits of full length resizing vs partial full length resizing. Meaning not having the case body having any alignment effect on the bullet in the throat.

Reloading: Partial Neck Sizing
by German A. Salazar
http://riflemansjournal.blogspot.com/2010/06/reloading-partial-neck-sizing.html

"Now the last scenario, a full-length sized case in which the neck is also fully sized. There is clearance at the neck and in the body of the case, the closest fit anywhere is the bullet in the throat. If the neck to bullet concentricity is good (although it needn't be perfect), then the bullet will find good alignment in the throat and the case body and neck will have minimal influence. Let's not forget that the base of the case is supported by the bolt face or the extractor to a certain degree as well; this is yet another influence on alignment. As you can see, there are several points from base to bullet that can have an effect. My procedure is to minimize the influence of those that I can control, namely the case body and neck, and let the alignment be dictated by the fit of the bullet in the throat and to some extent by the bolt's support of the base. Barring a seriously out of square case head, I don't think the bolt can have a negative effect on alignment, only a slightly positive effect from minimizing "case droop" in the chamber. Given that a resized case will usually have a maximum of 0.001" diametrical clearance at the web, this isn't much of a factor anyway."

I collected milsurp rifles and at one time had 13 British .303 Enfield rifles and understand the word "headspace" better than most people.

The Enfield rifle had replaceable bolt heads to adjust the rifles headspace. And military headspace is .064 minimum and .074 maximum. And the rifle below has had the headspace set from .058 to .084 and checking to see how much the cases stretch and thin when fired. And now this rifle has two bolt heads fitted to use depending on the cases rim thickness.

And below are my military and SAAMI headspace gauges for my .303 Enfield rifles.

And below is what happens when any rifle has too much head clearance and fired.

"BUT" if the case is properly fire formed the case will not stretch when fired.

And the amount of permissible head clearance depends on the quality of the case and the hardness of the brass.

Both cases below were fired in the same 1943 No.4 Enfield rifle with the same load. And as you can see there is a vast difference in case quality and the hardness of the brass. The Prvi Partizan case has thicker rims, is a larger base diameter and .010 thicker in the base web area.

And all the OP needs to do is take some case measurements and see how much he is reducing the case diameter after sizing the case.

A resized case for a semi-auto should be .003 to .005 smaller in diameter than its fired diameter for reliable extraction. And for a full length resized case in a bolt action the case should be .001 to .002 smaller than its fired diameter for reliable extraction. "The cartridge case should fit the chamber like a rat turd in a violin case".

 

[bigedp51]

Wouldn't excessive head space cause the primers to be pushed out?
Just wondering?
I thought that was a symptom of oversizing your cases

If you make a workup load with new cases starting at the suggested start load and work up, the primers will protrude until the chamber pressure is great enough the push the base of the case against the bolt face.

Example my 30-30 Winchester at 38,000 cup or 42,000 psi always has the primers protruding. And this is because the chamber pressure is not high enough to make the brass stretch. Meaning the only part of the case that is touching the bolt face is the primer.

So with lower chamber pressures the primer backs out of the primer pocket and the case is headspacing on the primer.

And when the primers are flush with the base of the case the chamber pressure was great enough to make the case conform to chamber dimensions minus any brass spring back.