Case Uneven Wall Thickness

[F. Guffey]

Originally Posted by F. Guffey View Post
How is it possible to prevent/avoid the case stretching between the case head and case body? (shoulder?)
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Fire the round in a chamber with -.001" head clearance

That is not possible if you use your firing pins because you have spent a lot of time convincing 'other reloaders' the firing pin drives the case into the chamber and it is so powerful it shortens the case as much as .005" between the datum/shoulder to the case head. And then, added to that' you have cases that shorten between the shoulder and case head when the bolt closes. the point is? If any of that is true you start with cases with .007" clearance.

I have busted primers with one of my rifles that has a killer firing pin. I did not pull the trigger on a loaded round meaning no bullet and no powder. Meaning I hit the primer in a case that was lighter. I busted primers in 5 different cases, when I extracted the case the primer was not protruding and the none of the cases shortened between the datum and the case head.

And again I keep saying you are leaving out one of the events in the sequence of events that happen between pulling the trigger and the bullet leaving the case.

F. Guffey

[F. Guffey]

(shoulder?)

I have suggested if you knew what you were talking about you would understand what happens when the case starts at the shoulder of the chamber when fired. I have said it is a bad habit to fire a case when the shoulder of the case is setting at the shoulder of the chamber.

And then I wasted my time talking about a friend that built a magnificent riles, he made the reamer he chambered the rifle and had 5 case head separations out of the first 10 rounds fired.

I informed him he could have determine that would be the outcome before he left the shop, I informed him I could have fixed the problem at the range long enough for him to fire form his cases in his newly built Wildcat rifle.

F. Guffey

And then there is that thing about doing like bench resters. They have been full length sizing cases for decades? And now you have it down to .001"/feeler gage size for clearance when avoiding full length sizing.

[Don Fischer]

Originally Posted by F. Guffey

Bart B. claims the firing pin shortens the case between the shoulder and case head as much as .005" when the firing pin strikes the primer. If you get yourself a pencil you can add the total it up with the bolt slamming the round into the chamber. I do not work in the claims department but there are a few that do; they claim the case shortens as much as .007" when chambered and fired (and there is something/an event they always leave out) so the question is: How is it possible to prevent/avoid the case stretching between the case head and case body.

And then we have members that fire cases 45 times with maximum loads with no serious/ ill effects.

F. Guffey

I noticed in an earlier post someone had spoken of an unbelievable number of round's fired in a single case with max loads. What I'd like to know, how does that work? I tend to fire close to and max loads in everything and I don't get anywhere near that many rounds. Long before that milestone the primer's start falling out of the pocket's!

[F. Guffey]

What I'd like to know, how does that work?

I do not know, the owner of the rifle built by a friend handed me case that had been fired at least 50 times, that case had trouble standing up straight when placed on the table. I asked the shooter when did he stop sizing his case because I was convinced the case could not be pulled out of the die when the ram was lowered.

F. Guffey

[Unclenick]

Originally Posted by Don Fischer

What I'd like to know, how does that work?…I tend to fire close to and max loads…Long before that milestone the primer's start falling out of the pocket's!

It doesn't work with near-max loads. Board member Hummer70 says he has one .308 Win case that has been reloaded 157 times. A great many benchrest shooters nurse theirs through 50 reloadings. The general approach to maximum case life is:

• Middling loads, not max loads. In many guns, these prove more accurate anyway. You have to test what you have to see if it applies to you.
• Anneal necks at roughly 10 round intervals (unless you overheat, in which case the brass gets weaker and you have to do it every 5 rounds or less).
• Minimize resizing.

On that last point, Hummer70 says he owns a very large number of .308 Win sizing dies. Each has been ground to prevent it over-resizing the cases he's chosen to use with a particular gun. Die necks have been honed out to match the brass and not to size them more than necessary to hold onto the bullet, so they need no expander run through them. Use Lake City or the relatively new Atlas Development Group cases that have had the head double-struck. Both have extra hard heads the will better resist letting primer pockets loosen.

[F. Guffey]

On that last point, Hummer70 says he owns a very large number of .308 Win sizing dies. Each has been ground to prevent it over-resizing the cases he's chosen to use with a particular gun

Grinding the bottom of the die reduces the length of the case from the case shoulder to the case head. To avoid oversizing the reloader is required in add to the bottom of the die to increase the ability of the die and shell holders ability to prevent reducing the length of the case from the shoulder to the case head.

And then there are short chambers. I size cases for short chambers; I measure the length of the chamber from the shoulder of the chamber to the bolt face. I have always thought grinding the bottom of the die and or reducing the deck height of a shell holder was a bad habit. And then there is grinding for the correct reason.

F. Guffey

[F. Guffey]

By design the die sizes cases to minimum length, for the 30/06 that would be .005" shorter than a go-gage length chamber.

And then there is full length sizing; reloaders can not pin it down because they have too many variations and tolerances.

F. Guffey

[old roper]

In Ackley's book Vol II page 78 is test done by Fred Huntington on Case Life with Full Length Resizing.

First test rifle was factory Model 70 30-06. Test cases 2-Rem,2-Win. Test loads 58gr/4350, 150gr Speer bullet @ 2895fps.

Number of times fired Winchester --55 and 50 times
Remington---52 and 36 times

1 Rem case split at neck @ 36th firing
2 Rem case split at neck @ 52nd firing
3 Win case split at neck @ 50th firing
4 Win case split at neck @ 55th firing
All cases resized after every firing and case lube but nothing inside necks. Had inside neck lube it should of prolong case-neck life.

Nobody anneal those case

Next test was Rem 721 222 and they test 3 cases but didn'r mention who's but they got pretty close to 100 reloads,fl sizing

[Bart B.]

Don Fischer says:

I tend to fire close to and max loads in everything and I don't get anywhere near that many rounds. Long before that milestone the primer's start falling out of the pocket's!

Having fired a couple hundred 7.62 NATO proof loads (67,500 cup, ~82,000 psi) in several Garands, most folks inspecting the fired case's primers said the were maximum loads and looked much like their handload's fired primers.

[F. Guffey]

In Ackley's book Vol II page 78 is test done by Fred Huntington on Case Life with Full Length Resizing.

Full length sizing is one factor, with full loads it is another matter. And then there is measuring before and again after. Factory case heads expand .00025" each firing, if the reloader has the ability to measure the diameter of case heads he has the ability to compare his reloads with factory loads.

I have fired cases that had .010" case head expansion, I have fired cases that were ejected with primer pockets that were so large I had to take the rifle apart to find the primer.

F. Guffey

[Unclenick]

Hummer70 chamber's his own barrels with custom reamer designs. You can, nonetheless grind standard resizing dies to fit even a standard match chamber if you plan on using one of the high deck height Redding shell holders.

[Metal god]

Fire the rimless bottleneck round in a chamber with -.001" or -.002" head clearance.

Correct , the key word in the question is stretch . Cases can expand with out stretching then spring back . Brass has elasticity and the key is to avoid the case from stretching . By having .002 head clearance or less allows the case to expand but prevents the case from stretching .

[Bart B.]

Originally Posted by Metal god

Correct , the key word in the question is stretch . Cases can expand with out stretching then spring back . Brass has elasticity and the key is to avoid the case from stretching . By having .002 head clearance or less allows the case to expand but prevents the case from stretching .

My use of "-.002" head clearance means "minus .002" head clearance. Case head clearance formula for rounds headspacing on their shoulder equals chamber headspace minus case headspace. If a 308 chamber headspace is 1.632" and case headspace is 1.634" head clearance is -.002". The bolt will close hard on such rounds.

Case length typically means head to mouth. Case headspace typically mean head to shoulder. Most cases have more headspace and less length after firing.

[F. Guffey]

If a 308 chamber headspace is 1.632" and case headspace is 1.634" head clearance is -.002". The bolt will close hard on such rounds.

The case does not have head space. I off set the length of the chamber with the length of the case from the shoulder/datum to the case head. Many reloaders got into reloading late in life and that is good but the late start caused them to have a bad start.

A reloaders with a good understanding of the Wilson case gage dies not have problems making this stuff up. The Wilson case gage is a datum based tool. There should be nothing complicated about that because the case has two lengths, one is measured from the datum forward to the end of the neck and the other length is measured from the datum to the case head.

A reloader with a good understanding of the Wilson case gage does not make up stuff about what happens to the case when fired.

I know it boggles the mind but I have no problem with cases increase in length from the datum to the case head and shorten from the datum to the end of the neck. To understand 'what happened' the reloader must understand where the case positioned in the chamber when it fired.

According to most reloaders the case stretches between the case head and case body. To understand that the reloaders must know where the case was when it was fired,

And then there are rimmed and belted cases: The problem with solving problems with rimmed and belted cases is complicated by component manufacturers. The component manufacturer does not make cases for reloaders that know what they are doing.

F. Guffey

[Metal god]

If a 308 chamber headspace is 1.632" and case headspace is 1.634" head clearance is -.002". The bolt will close hard on such rounds.

I did not read your last post to mean that . Oh yeah if you have a case sized +.002 then the headspace of the rifle . Not likely going to get any case movement let alone case stretch .

[Bart B.]

The problem with solving problems with rimmed and belted cases is complicated by component manufacturers. The component manufacturer does not make cases for reloaders that know what they are doing.

With due respect its author, 'tis most opposite and rediculous I've seen in print compared to facts and reality.

[F. Guffey]

With due respect its author, 'tis most opposite and ridiculous I've seen in print compared to facts and reality.

Do a search for a reloader that measures the thickness of a case rim, we both know that will not happen and then try to find a belted case that will off set the chamber head space in a belted chamber.

Component manufacturers do not manufacture cases with different rim thicknesses. But if they did I would know what to do with them. I have measured the thickness of rimmed cases and I have refused to use them because I thought they were too thin. I have also measured cases for case head thickness and refused to use them for the same reason, too thin.

I said I did find some clandestine cases that appeared to be designed to off set the length of the chamber from the shoulder to the case head. At the time it meant nothing to me because I did/do not need the cases so I placed the cases in a drawer of collectable cases and no I do not have enough ambition to convince anyone the cases in my collectable drawer are collectable.

F. Guffey

If the component manufacturer made cases for me I would occasionally find a case with a rim that was too thick.

And then there is the 30/06 case, I use the 280 Remington case to off set 30/06 chambers that are too long from the shoulder to the bolt face. How is it possible to miss fitting the case to the chamber when there is .051" to play with. And then R-P made 35 Whelen cases that had a straight case body, meaning the case did not have a shoulder, it was up to the reloader that knew where the shoulder was supposed to be.

And again how could a reloader miss, the straight wall case was 2.650" long from the case mouth to the case head.

How could anyone miss? Back to the top, R-P made the cases for a reloader/case former/ wildcat type. I settled on the 280 Remington case.

F. Guffey

[F. Guffey]

Back to making cases for me: Not once but I have ordered cases from Pat's tumbling by the thousands. 30/06 pull down unfired and most without crimped primers. Again, I am the only one that sizes the case to off set the length of the chamber from the shoulder to the bolt face.

When I return home or he shipped the cases the first thing I did was neck 400 of the cases up to 338/06 and 35 Whelen. It had nothing to do with needing 338/06 cases or 35 Whelen, it had to do with the 338/06 cases and the 35 Whelens were a good place to start when forming cases.

And if the cases were not good cases they would not survive stretching the cases necks up to 35 Whelen.

F. Guffey

[Bart B.]

...try to find a belted case that will off set the chamber head space in a belted chamber.

I have lots of them. When loaded, chambered and fired, their shoulder is against the chamber shoulder and their belt front edge is a few thousandths inch back from the chamber headspacing step. their head is a couple thousandths off the bolt face.

I've always full length resized fired belted cases moving their shoulder back about .001" so that is their headspace reference. Their belt's front edge "floats" a few thousandths back from the chamber ridge new cases usually headspace off from.

[F. Guffey]

I've always full length resized fired belted cases moving their shoulder back about .001"

It is impossible to move a shoulder back with a die that has case body support. And when a reloaders tries to explain it they run out of gas and claim it is all Semantics.

The first thing the shoulder/case body wants to do is bulge, back to Lyman and Dillon; both suggested crimping the neck of a bottle neck case can be a bad habit. They Lyman suggested crimping can reduce bullet hold, and then there is tension, all of my gages are marked off in pounds, even the tension gages.

F. Guffey

[joneb]

Quite a few years ago I processed 100 + F-C 308 Win. range pick cases. I kept 60 of these to reload the other 40 + went to the scrap bucket. The ones I scrapped had varying wall thickness at the neck, this means the wall thickness varies through the body of the case.
Of those 60 case I came up with three groups by weight, it was a bit of work for this F-C brass that doesn't see many reloadings before the primer pockets get loose.

[Bart B.]

Originally Posted by joneb

Quite a few years ago I processed 100 + F-C 308 Win. range pick cases. I kept 60 of these to reload the other 40 + went to the scrap bucket. The ones I scrapped had varying wall thickness at the neck, this means the wall thickness varies through the body of the case.

If their heads were all square with case axis, I would have turned all their necks to uniform thickness then used a sizing die whose neck ID is .002" smaller than bullet plus 2X neck wall thickness. Uneven case wall thickness behind the neck isn't detrimental to accuracy.

Out of square case heads are detrimental and add 1/2 MOA or more to group size

[Metal god]

Out of square case heads are detrimental and add 1/2 MOA or more to group size

See , I knew there was a reason I can only get 5/8 moa groups .

[joneb]

Out of square case heads are detrimental and add 1/2 MOA or more to group size

The bolt face in my rifle seems pretty square I'm not sure about the firearms that shot the cases I picked up.
After cleaning. full length sizing, trimming and uniforming the flash holes I set my neck trimmer to a case that had a uniform neck wall thickness so it just skimmed the neck. With the trimmer set I was able to identify the cases with inconsistent case wall thicknesses, after culling out 40 of the F-C cases the remainder where loaded with 16gr of Blue Dot and Nosler 125gr BT factory seconds. These fire forming loads turned out to be very accurate grouping on average at .75" @ 100 yards, I had to re-zero my scope for these loads and they worked very well for rockckucks and coyotes.
What I really liked about this load is the accuracy did not diminish from repeated firings, the barrel stayed surprisingly cool.
After that the cases were neck sized and loaded with standard 308 Win loads.
All of my shooting with this Blue Dot load was done on +or- 10 degree shooting angle so with a approx. 45% load density it could be position sensitive?

[Metal god]

The bolt face in my rifle seems pretty square I'm not sure about the firearms that shot the cases I picked up.

One way to check case head squareness is to line the cases up with a straight edge . Look down them to see if any are out of alignment .

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