Hi,

I use a Lee Trimmer to trim my cases and find that cases fired from my .30-06 always have to be trimmed and usually a lot of brass is trimmed off by the cutter. I think the stretching is excessive.

Is this indicative of excessive headspace?

Another thing that I have noticed is that all loads, even mild hand loads and factory loads e.g. PMP 180 gr have flattened primers. This seems to confirm that the headspace is excessive.

I have just recently turned my die out by a full turn so that cases are not fully resized. Time will tell if the amount f brass being trimmed off is reduced.

Besides shortened case life, is their any other problem(s) or dangers caused by excessive headspace?

How would a gunsmith rectify this?

Cheers

Learn how to set your dies correctly.
"Headspace" is a physical distance between the bolt face and a datum line on the shoulder, the difference between "not enough" and "to much" is IIRC .006 (.15mm).
What your seeing is a result of excess clearance between the case and the chamber, and this is a direct result of you pushing the shoulder back to far.

What tailgunner said.

Yes, it appears that you have "excessive headspace". However, headspace, being the relationship between the length of the "stopping point" on the case (whether that be shoulder, belt, rim, or mouth), you can "normalize" headspace simply by fireforming your brass (shooting it once in your gun) then resizing it only so that it will redily re-enter the chamber, not so as to set back the shoulder again. Upon subsequent firings it will have very little tendency to stretch, and you will also avoid the dreaded potential case head separation which will inevitably occur at the pressure ring about 1/4-inch in front of the rim. Case head separations can, at best, temporarily disable the gun until the forward portion of the case can be removed, and at worst, injure the shooter with high pressure gas and brass particals blown back into his face.

Only if your headspace were so long as to cause erratic ignition would it be advisable to have the gun worked on by a gunsmith. The solution would be to set the barrel back by a thread then run a chambering reamer into the old chamber to make it within factory specs. Be advised, however, that factory chambers are usually on the long side and factory ammunition is usually on the short side, thus creating an "excessive" headspace situation in most rifles with factory ammunition. This is only a problem if you reload the cases and continue to set the shoulders back to near minimum dimension.

Howdy!
Can you please post a pic of a fired unsized factory case so that we can see the amount of primer flattening.
It may not be a headspace issue at all, you may in fact have a minimum chamber that raises pressure slightly.
Factory chambers are getting tighter these days due to the "hammer forging" process, not all chambers are cut anymore!

Case stretching or lengthening in the neck is caused by the die, not the rifle, you only need to trim them once they've reached maximum length.
Excessive trimming is hard to keep note of, you must take note of the number of times cases reach the maximum length and require trimming, once it has reached it's fifth trim it's time to turf them in the trash!
Normally you trim to .010" below max, and it should take a few firings to grow back to the max dimension.
If it's happening more frequently than that, your sizing button may be too large and is 'drawing' brass with it as it is withdrawn from the die while you size your cases.
To eliminate this, use powdered graphite on the insides of your case necks, a case neck brush dipped into the graphite and shaken to remove any excess is best, it will not contaminate anything in your cases, and will completely arrest any lengthening of the case necks in your die.

quote:

Originally posted by Stonecreek:
This is only a problem if you reload the cases and continue to set the shoulders back to near minimum dimension.

Which I is what I have been doing. I will only neck-size cases in the future!

Thanks for the help.

quote:

Originally posted by 416RigbyHunter:
To eliminate this, use powdered graphite on the insides of your case necks, a case neck brush dipped into the graphite and shaken to remove any excess is best, it will not contaminate anything in your cases, and will completely arrest any lengthening of the case necks in your die.

Thank you for that great advice!

quote:

Originally posted by umshiniwam:
I use a Lee Trimmer to trim my cases and find that cases fired from my .30-06 always have to be trimmed and usually a lot of brass is trimmed off by the cutter. I think the stretching is excessive.

Is this indicative of excessive headspace?

Not in itself. It is probably an indication that your chamber is quite a bit larger than your FL sizing die. Both chambers and dies come in all possible sizes, if they are not particularly well matched, your cases will stretch a lot with each firing/sizing.

Factories often cut chambers on the large side to compensate for the fact that (factory) ammo can have fairly large tolerances. Likewise, die manufacturers tend to cut their dies on the small side, to ensure cases sized will chamber in all chambers.

By far the biggest contribution to case stretch comes from the sizing of the case walls. The more they are squeezed (i.e. the bigger the difference between chamber and die dimensions), the more the case will stretch.

Whether in your particular case, there is an additional problem with excessive headspace, I'll leave open. But excessive headspace is often measured in .001 of an inch, excessive case stretching in .010 of an inch...

- mike

P.S. I should say, that cases with a sloping shoulder tend to stretch more than cases with steep shoulders. In my experience, the .30-06 is not particularly prone to stretching, though, cases such as the 6.5x55 are worse, IMHO.

P.P.S. the idea that case stretching comes from necks being pulled longer as the expander ball is withdrawn is largely a myth, IMHO. I don't want to be argumentative, and people are free to believe what they want, but you also get case stretching when you size without an expander, and where would that then arise...

When brass is squeezed in the sizing operation, the material only has one way to move, and that is forward. As you progressively turn in your sizing die, you will actually find that your case head-shoulder dimension INCREASES when the case is sized. Eventually, the die is adjusted so deeply, that it will touch the case shoulder, and push it back. Now all that stretching has to show up in the overall case length, and if excessive, you will have to trim....

P.P.P.S. if you don't like trimming, measure the actual length of YOUR chamber. Most (factory) chambers are cut a good deal longer than what is specified by the cartridge specs. That means you can safely let your cases grow beyond what the spec states as max length. But to do this safely, you MUST establish the max length of YOUR chamber. www.sinclairintl.com sells a little gizmo called a "chamber length gauge" (I believe - I can't access that website here from work). That will allow you to measure the length of YOUR chamber, and likely reduce the amount of trimming necessary significantly.

quote:

Originally posted by umshiniwam:

quote:

Originally posted by Stonecreek:
This is only a problem if you reload the cases and continue to set the shoulders back to near minimum dimension.

Which I is what I have been doing. I will only neck-size cases in the future!

Use the search function in here to locate "Partial Full Length Sizing" (or PFL or PFLS). This is a way to set up your FL sizing dies to only push back the case shoulder as little as required (preferably .001-.002") for smooth chambering. Our esteemed member "Hot Core" has done a good write-up on how to set your dies up for PFLS.

You can certainly rely on neck sizing, some guns like neck sized cases. Others, however, don't. And what you will find, is that your cases will chamber more and more stiffly, requiring more force to chamber, as they are repeatedly fired and (neck-)sized. Eventually, you will have to to FL size, and then you might as well learn to set up your FL sizing dies properly in the first place.

I personally have come to rely on PFLS for practically all my resizing. In contrast to "Hot Core" I use a headspace gauge to ensure my die settings provide the shoulder push back I require. But there is more than one way to skin a cat, and Hot Core seems to be successful with his method as well.

The important thing is that you don't set back your case shoulders excessively when sizing.

- mike

Thamsk fpor the advice Mike.

When I referred to "neck sizing" above I actually meant PFLS. I realise now that the two terms are not interchangeable.

I will do the suggested search to learn more.

Cheers

quote:

a case neck brush dipped into the graphite...will completely arrest any lengthening of the case necks in your die.

Not really. Virtually all of our case lengthening occurs from excessive shoulder set back during FL sizing, very little of it is due to expander drag.

The Lee Trimmer that uses a case length gage, cutter & shell holder will remove brass after every firing. Normal. When using a different case trimmer like a Lyman, rifle brass is cut back .010" from the maximum length. This method means you do not have to trim brass every loading as it has room to grow. This Lee trimmer cuts close to the minimum trim length each and every time. If you have a headspace problem with your firearm, the brass will let you know. Shiny rings appear in the web area and/or can be in the middle of the case body. See signs of separation here> link

quote:

Originally posted by mho:

quote:

Originally posted by umshiniwam:
I use a Lee Trimmer to trim my cases and find that cases fired from my .30-06 always have to be trimmed and usually a lot of brass is trimmed off by the cutter. I think the stretching is excessive.

Is this indicative of excessive headspace?

Not in itself. It is probably an indication that your chamber is quite a bit larger than your FL sizing die. Both chambers and dies come in all possible sizes, if they are not particularly well matched, your cases will stretch a lot with each firing/sizing.

Factories often cut chambers on the large side to compensate for the fact that (factory) ammo can have fairly large tolerances. Likewise, die manufacturers tend to cut their dies on the small side, to ensure cases sized will chamber in all chambers.

By far the biggest contribution to case stretch comes from the sizing of the case walls. The more they are squeezed (i.e. the bigger the difference between chamber and die dimensions), the more the case will stretch.

Whether in your particular case, there is an additional problem with excessive headspace, I'll leave open. But excessive headspace is often measured in .001 of an inch, excessive case stretching in .010 of an inch...

- mike

.....

mike, What if this situation were to occur with factory loads?

quote:

Originally posted by RaySendero:
mike, What if this situation were to occur with factory loads?

Let me see if I understand you correctly.

I think you imagine a scenario, in which you fire factory ammo in your rifle, resize the once fired cases, and now find that these cases are longer than book max. Correct??

You then wonder, what would be the cause of this (unexpected) growth beyond book max? Correct??

If I have understood you correctly, then the reason is the same as for reloaded ammo: excessive lengthening of brass via a fire/resize process is likely to be caused by some combination of a large chamber and a (comparatively) smallish die.

Hope this helps, otherwise holler...

- mike

quote:

Case stretching or lengthening in the neck is caused by the die, not the rifle, you only need to trim them once they've reached maximum length.
Excessive trimming is hard to keep note of, you must take note of the number of times cases reach the maximum length and require trimming, once it has reached it's fifth trim it's time to turf them in the trash!
Normally you trim to .010" below max, and it should take a few firings to grow back to the max dimension.
If it's happening more frequently than that, your sizing button may be too large and is 'drawing' brass with it as it is withdrawn from the die while you size your cases.

I don't believe this. It's been repeated so much, it's become fact for most reloaders, thanks to the internet.

quote:

P.P.S. the idea that case stretching comes from necks being pulled longer as the expander ball is withdrawn is largely a myth, IMHO. I don't want to be argumentative, and people are free to believe what they want, but you also get case stretching when you size without an expander, and where would that then arise...

Exactly! If you think, or believe the above nonsense, then a light coating of your case lube inside the neck will prevent the expander ball drag. I keep a nylon brush on the bench that I lightly lube with whatever case lube I'm using. A quick pass on the inside of the necks makes the expander slide through without drag.

There's two gauges out there for actually measuring the amount of shoulder set-back you're getting. Hornady makes one that is universal, RCBS makes one that is caliber
specific. It allows you to set the sizing die to ONLY set back the shoulder to where it chambers freely, but does not create excess headspace.

Hornady LNL gauge

RCBS precision mic

quote:

Originally posted by mho:

quote:

Originally posted by RaySendero:
mike, What if this situation were to occur with factory loads?

Let me see if I understand you correctly.

I think you imagine a scenario, in which you fire factory ammo in your rifle, resize the once fired cases, and now find that these cases are longer than book max. Correct??

- mike

Uh - NO, Just grow with firing not resized.


Here's some numbers:

New Case OL 2.213''
New Neck Base OL 1.870''
New Shoulder OD 0.400''

Fired Case OL 2.235''
Fired Neck Base OL 1.900''
Fired Shoulder OD 0.408''

Case growth (length) is caused by pulling the resizer ball thru the neck..........

quote:

Originally posted by RaySendero:
Uh - NO, Just grow with firing not resized.

Here's some numbers:

New Case OL 2.213''
New Neck Base OL 1.870''
New Shoulder OD 0.400''

Fired Case OL 2.235''
Fired Neck Base OL 1.900''
Fired Shoulder OD 0.408''

OK, got ya.

If it quite common that (factory) chambers are cut on the larger side - they need to digest pretty much any ammo, and pressures will be a bit lower. So factories often err on the side of caution.

Factory ammo, on the other hand will often be manufactured on the low side of specs. It needs to fit in practically any chamber imaginable.

In any event, the chamber needs to be larger than the case for the ammo to chamber. After firing, the fired case will have expanded to (approximately) match the size of the chamber.

Of the numbers you quote, the only worrying one is the one for over-all length (or Case OL as you have labelled it). The increase in this number reflects that the head-shoulder dimension of the chamber was quite a bit larger than that of the factory (unfired) brass. Fortunately, brass is a pretty mallable material, and the case stretched to match the chamber size. This is a pretty nomal occurrence, although the stretch you have observed is probably on the longer side.

If you now sized the case back to factory unfired dimensions, and fired it in the same chamber again, you would re-encounter the stretch. Eventually, the brass would be unable to stretch leading to a case head separation - a potentially dangerous condition!! To avoid this, it is important that the case shoulder is not set back excessively in the sizing operation. Then you should be good to go, even with brass that stretched quite a lot in its initial firing. All brass must be inspected for incipient head separations, though.

Hope this helps.

- mike

quote:

I use a Lee Trimmer to trim my cases and find that cases fired from my .30-06 always have to be trimmed and usually a lot of brass is trimmed off by the cutter. I think the stretching is excessive.

Is this indicative of excessive headspace?

Not necessarily. I find that on new brass, the first trimming removes the most material from the neck. I took one set of LC64 308 brass 22 or 24 reloads in a M1a. This was once fired brass. I full length resize with a small base die and I use cartridge headspace gages and size to gage minimum. My case shoulders are typically set back .003” from the chamber, but if it is a maximum chamber, then the shoulder gets set back the full .006”. First trimming took off at least .010 to .015 of sized neck. I trim my 308 brass to 2.00 or so. Subsequent trimmings were .003”, but as I continued to shoot the stuff, I was trimming less than .001” toward the end. If I shot the stuff in another M1a, or used a different sizing die, trim removal went back up to .003”, but stabilized back to .001” on the next sizing with the same die. I have no idea what was going on with the different rifles and dies, but I do believe the brass was work hardening and stretching less over time.

I always lube the necks because it is a lot easier to pull the expander button through the neck.

Now this idea was fought out on another thread, but you really don’t know what is going on unless you have gages to measure. There are some troglodytes who think gages are un necessary, and will chase you around with their mighty clubs for suggesting otherwise, but hey, what do flint nappers know about the mechanical age?

I recommend you buy a simple Wilson type cartridge headspace gage. This gage is cut large between the shoulder and the base so you can drop in fired rounds and see it your chamber is between Go and No Go. I have verified with chamber headspace gages, that the ledges in the Wilson gage are correctly cut. If your fired round sticks out the back, then your chamber is overmax. There are exceptions due to bad brass. Some cases are so poorly made they are almost semi rimmed and the rim interference causes issues. And maybe if your chamber is crooked, or it is so large that Zeppelins park there at night. Which if true, I would evict the Zeppelins and sell the rifle.

Set up your reloading dies using a gage. Size your cases so they are not below the smaller "Go" ledge.

quote:

Another thing that I have noticed is that all loads, even mild hand loads and factory loads e.g. PMP 180 gr have flattened primers. This seems to confirm that the headspace is excessive.

Not necessarily. Understand that I am a heretic. A total apostate, condemned to an eternity in hell by conventional wisdom. I lubricate the cases used in my Garands and M1a’s. I do this for increased case life, which is why I was able to take 100 cases, minus the amount the range gods hid in the weeds, for over 20 reloads in a M1a. No one ever takes brass that far without case head separations, I had exactly zero.

I full length resize my brass because function is more important than case life. I absolutely must have safe, accurate and reliable function during high power matches. I know of no Master Class or higher competitor who does anything but full length resize their cases. Shooters who partially resize, neck size, will have function issues. That is not a big problem on the score sheets of the duffers who do this, but if you want to win, your ammo must be 100% functional at all times.

I found in load development, with mild loads and lubricated cases, I got nice rounded primers. As the charge increased, at some point the primer flattened out. However, if I started out with mild loads and dry cases, I always got flattened primers. After puzzling on this, I figured out that with dry cases, the primer backed out to the bolt face and then the case finally stretched back to the bolt face and stuffed the primer back in. So the primer was always going to be rather flattened. The reason primers were not flattened with the lubricated cases was that the case was unable to grip the chamber walls and slide back to the bolt face before the primer was able to back out. At some point in the load development, the internal pressures of higher loads flattened out the primers in the lubricated cases.

So what I learned about this was for the very devote orthodox types who swab their chamber clean between each shot and wear cotton gloves so their chemically clean cases won’t get any nasty finger oil on them, they will get flattened primers at mild loads. And this is a good reason not to pay any attention to primer indications till they pierce or leak Because primers lie.

quote:

Besides shortened case life, is their any other problem(s) or dangers caused by excessive headspace?

Excessive rifle chamber headspace, combined with excess cartridge shoulder set back will lead to case head separation. . Brass is always operating above its yield or it would not provide a gas seal. With dry cases and chambers the neck and shoulder of the case sticks to the chamber front and then as pressure builds, the rear of the case is stretched to the bolt face. Brass is only meant to stretch .006” at most the first firing. Reloaders will take that stuff and then resize it, and then you get case head separations down the road.

If you are truly concerned about headspace, I would recommend that you take your rifle to a gunsmith and have him gage your chamber. As long as he tells you it is inbetween Go and No Go , you are safe to go. This should be unnecessary with a factory new rifle with matching bolt and serial numbers, but if this bothers you, get it verified. Then if you set up your die with these cartridge headspace gages, and only bump the shoulder back around .003”, you will be able to take your brass an exceptional number of reloads.

quote:

I figured out that with dry cases, the primer backed out to the bolt face and then the case finally stretched back to the bolt face and stuffed the primer back in.

That's true, so far as it goes. But it doesn't go far enough to cover the whole story.

Primers back out due to their own detonation, it isn't the relitively slow build up of chamber pressure that does it. Ergo, your lubed cases are not the reason your higher pressure loads don't flatten your primers. And NO primer can back out unless there is slop in the cartridge to chamber fit, AKA, excess headspace". Headspace is controllable in sizing by the reloader so it becomes irrelivant, or should.

I've been doing this since '65 and have NEVER seen a mild/moderate charge create a flattened primer in any cartridge and all my rounds are cleaned of any lube before using in my bolt/lever guns; don't have any experience with autos.

All a min/max chamber cartrige gage from Wilson, etc, can tell us is if the finished ammo meets SAAMI specifications in order for it to chamber in any rifle every made for that cartridge. Or, to put it properly, using such a gauge almost guarantees the finished ammo won't ideally fit an individual rifle as well as it could and should. For that we need a proper "head space" gage we can use to actually read the fired and resized shoulder length in thousanths; Hornady LnL or Sinclair, Innovative Technologies, RCBS Precision Case Mic, etc.

quote:

I've been doing this since '65 and have NEVER seen a mild/moderate charge create a flattened primer in any cartridge and all my rounds are cleaned of any lube before using in my bolt/lever guns; don't have any experience with autos.

I may have mis stated, at very light load levels the primers come out round. Regardless of dry versus lubed.

This is an example of dry cases with a light load. The load was not high enough to stretch the case to the bolt face, and the primers are backed out, and rounded.


But when developing loads in a 308 and a 168. Starting at 39, 40 grains IMR 4895, with lubed cases the primers are rounded. Then I hit a point where the primer flattens. And that is above 41.5 grs with LC cases. That is my maximum load.

But if I started with dry cases for the same loads, primers are flat at charges where lubricated cases give me rounded primers.

So what causes this, if it is not the lubrication?

As for excessive headspace, you would need to define this. I view excessive headspace for a rifle to be a headspace distance that exceeds the No Go gage. For a cartridge I would consider excessive headspace when the shoulder is pushed under the Go gage. Anything between Go and No Go for the rifle and cartridge I do not consider excessive headspace.

As for an ideal fit, someone shooting a bench rest rifle



will see effects that I will never see shooting one of these



or these



And the bench rest shooter will have one heck of a time shooting his rifle standing. But I won't

quote:

By slamfire:
but you really don’t know what is going on unless you have gages to measure. There are some troglodytes who think gages are un necessary, and will chase you around with their mighty clubs for suggesting otherwise, but hey, what do flint nappers know about the mechanical age?

Case Gauges are as useful as obummmmer in the Oval Office. Only a total FOOL would suggest Thingy Gauges are the only answer to the problem that umshiniwam believes he is experiencing.
-----

Hey umshiniwam, Go up to the "Find" Button at the top of the page and type in P-FLR. If you are using a Bolt Action, that has a 99.9% chance of resolving the issue.

If however your rifle is a semi-auto, pump, or any rifle used in Dangerous Game country, then you need to Full Length Resize. This does shorten Case Life, but is necessary to provide the highest possible Feed reliability.

But, there is no need to totally waste money on Fool Thingys to resolve your concern.

Best of luck to you.

quote:

Only a total FOOL would suggest Thingy Gauges are the only answer to the problem that umshiniwam believes he is experiencing.

EEK! Gotta run. Trog on my tail. They may be flint nappers, but they hit hard.

Thanks to all for sharing information.

I need to take the rifle in to a gunsmith to have some stock work done so I will ask him to check the headspace while he is at it.

After reading your input, I suspect that my rifle (a BSA) has a chamber which is within spec but on the large rside, and as I use a Lee Trimmer which always will trim to minimum allowed case length, it will always removed brass.

I should probably invest in a decent case trimmer. What do you guys use to trim cases?

Also, I will use P-FLR in the future.
Cheers!

quote:

Originally posted by umshiniwam:
What do you guys use to trim cases?

Wilson with Sinclair stand and micrometer. Nice setup, if slightly pricey...

quote:

Also, I will use P-FLR in the future.

Good idea.

- mike

quote:

Originally posted by SlamFire:

quote:

Only a total FOOL would suggest Thingy Gauges are the only answer to the problem that umshiniwam believes he is experiencing.

EEK! Gotta run. Trog on my tail. They may be flint nappers, but they hit hard.

Slamfire, well taken. Hot Core seems to take anybody using (or worse, recommending - shudder!) a headspace gauge as a personal affront. This is a regular theme in here, so much I once felt the need to comment in the following fashion (from a different thread):

quote:

Varmitshooter, you can safely ignore Hot Core's comment. Although a very experienced reloader and (I assume) in general an intelligent guy, Hot Core seems to suffer from pavlovian conditioning to the term "Stoney Point Headspace Gauge".

It seems every time the poor lad encounters the term, he develops a bad case of frothing at the mouth, and has to jump into the discussion regardless of whether he has anything constructive to offer or not. I'm not quite sure if there is a scientific term for his condition, but we get to observe it regularly here.

Personaly, I don't quite get why the use of different methods and tools has to be cause for name calling - as in "total FOOL"?? We all try to be polite when we talk about PFLS, and always observe that Hot Core prefers this method, and we might prefer another. But for Hot Core there seems to be only his way or the highway, and good manners be darned. I'm not quite sure I understand the motivation??

- mike

Hey mho, I see you have "selective reading and comprehension abilities".

I was responding to the 100% complete and moronic highlighted portion of the following:

quote:

By slamfire:
but you really don’t know what is going on unless you have gages to measure. There are some troglodytes who think gages are un necessary, and will chase you around with their mighty clubs for suggesting otherwise, but hey, what do flint nappers know about the mechanical age?

If you don't like me responding to fools who attack me - then both of you.

Fair enough Hot Core, if you think slamfire stepped on your tail, I guess you can step on his.

I tend to agree with slamfire on the use of headspace gauges, but I accept the fact, that you (and others) seem to get along well without. We agree on the idea of PLFS, but use different methods to get there.

- mike

quote:

Originally posted by umshiniwam:
Thanks to all for sharing information.

I need to take the rifle in to a gunsmith to have some stock work done so I will ask him to check the headspace while he is at it.

After reading your input, I suspect that my rifle (a BSA) has a chamber which is within spec but on the large rside, and as I use a Lee Trimmer which always will trim to minimum allowed case length, it will always removed brass.

I should probably invest in a decent case trimmer. What do you guys use to trim cases?

Also, I will use P-FLR in the future.
Cheers!

You can continue to use the Lee trimmer. Just measure your trim length after FLRSing and wait till cases reach the maximum length before trimming.But you will need a vernier caliper or gauge to measure.I use the Lyman trimmer.

Thanks mho for the additional post. I've always thought we agreed more than we disagreed.

And I agree with you that if slam feels better using the Head Space Gauges, then that is what he should do. Everyone should use the Methods that make sense to them.(Even if they are a total waste of time and money. )

quote:

Originally posted by umshiniwam:
I use a Lee Trimmer which always will trim to minimum allowed case length, ...I should probably invest in a decent case trimmer. What do you guys use to trim cases? ...

I use the Lee Trimmers too. They provide a more consistent length than the Lathe style cutters for me. You can spend more here and end up with less accuracy on the length.

Best of luck to you.

quote:

Originally posted by grizz:

quote:

Case stretching or lengthening in the neck is caused by the die, not the rifle, you only need to trim them once they've reached maximum length.

Excessive trimming is hard to keep note of, you must take note of the number of times cases reach the maximum length and require trimming, once it has reached it's fifth trim it's time to turf them in the trash!
Normally you trim to .010" below max, and it should take a few firings to grow back to the max dimension.
If it's happening more frequently than that, your sizing button may be too large and is 'drawing' brass with it as it is withdrawn from the die while you size your cases.

I don't believe this. It's been repeated so much, it's become fact for most reloaders, thanks to the internet.

quote:

P.P.S. the idea that case stretching comes from necks being pulled longer as the expander ball is withdrawn is largely a myth, IMHO. I don't want to be argumentative, and people are free to believe what they want, but you also get case stretching when you size without an expander, and where would that then arise...

Exactly! If you think, or believe the above nonsense, then a light coating of your case lube inside the neck will prevent the expander ball drag. I keep a nylon brush on the bench that I lightly lube with whatever case lube I'm using. A quick pass on the inside of the necks makes the expander slide through without drag.

There's two gauges out there for actually measuring the amount of shoulder set-back you're getting. Hornady makes one that is universal, RCBS makes one that is caliber
specific. It allows you to set the sizing die to ONLY set back the shoulder to where it chambers freely, but does not create excess headspace.

Hornady LNL gauge

RCBS precision mic

I should have clarified this statement but rushed the post. I clearly stated, "If your expander is TOO LARGE it MAY be drawing brass as it's withdrawn!"

quote:

P.P.S. the idea that case stretching comes from necks being pulled longer as the expander ball is withdrawn is largely a myth, IMHO. I don't want to be argumentative, and people are free to believe what they want, but you also get case stretching when you size without an expander, and where would that then arise...

Most case lengthening occurs from FL sizing, the brass has to go somewhere from the case body as it is squeezed back to size. Which causes the necks to lengthen whether you use an expander or not!
The expander ball CAN lengthen the neck/shoulder if it is tight, they all should be polished to .0015"-.002" under bullet diameter to work correctly. Measure a case before and after Neck sizing only, if the sizing button is too large it MAY lengthen the base to mouth measurement and, powdered graphite can arrest this.

quote:

I keep a nylon brush on the bench that I lightly lube with whatever case lube I'm using. A quick pass on the inside of the necks makes the expander slide through without drag.

If you think this is BS, then why do you lube the insides of your case necks?

Necks- In 243win when the loaded rounds neck diameter is .276" the maximum, the necks will thin with repeated sizings, using standard FLRS dies using an expander,lubed. After a certain point, the neck wall thickness no longer gets thinner. Where does this brass go? Bushing dies do not seem to have the same effect on neck wall thickness when not using an expander.

I thought that the neck wall got thicker and uneven, and hence the need to outer neck turn after several reloads.

I am not that experienced would like to learn....

I'll be honest to you, I have never measured my neck wall thickness and compared new to well used cases. So I can't tell you whether the neck wall thickness varies (in one direction or the other) through repeated reloading.

What I do know, is that brass work hardens over time. It is therefore not the same to work with new brass, as opposed to brass reloaded and fired multiple times. This is most apparent if you work with a die giving you comparatively little neck tension - e.g. the Lee Collet Die. In such a setup, new(-ish) brass may be fine to reload, and well used brass may give you insufficient (or varying) neck tension.

It is probably rare that one decides to (outside) neck turn brass when it gets older. The fix for work hardening is annealing - or pitch the brass and use a new batch. Neck turning is primarily used to either 1) adapt brass to tight necked (custom) chambers, or 2) to ensure uniform neck wall thickness. It is questionable whether neck turning is the way to go in an (oversize) factory chamber, as it will cause necks to be worked more in the firing/reloading process.

- mike

quote:

Originally posted by mho:
I'll be honest to you, I have never measured my neck wall thickness and compared new to well used cases. So I can't tell you whether the neck wall thickness varies (in one direction or the other) through repeated reloading. ...

Oh - MY - GOSH!!!! How can you possibly get by without knowing that measurement to the 0.0000000000X" level??? Obviously time for (totally wasting $$$ on) a new Measuring Thingy.

There there now, HC, we should not be carried away with wanton irony...

- mike

quote:

Originally posted by mho:
I have never measured my neck wall thickness and compared new to well used cases.

the Lee Collet Die. In such a setup, new(-ish) brass may be fine to reload, and well used brass may give you insufficient (or varying) neck tension.



- mike

Do you think smashing the brass neck against the mandrel might thin it? Do a test, start with new brass, measure the loaded rounds neck diameters at each reloading, see if it thins???? It may not be work harding of the brass at all??

I've never measured them but one would think that the neck would become more uniform after several firings rather than less.

RAY: [quote]Here's some numbers:

New Case OL 2.213''
New Neck Base OL 1.870''
New Shoulder OD 0.400''

Fired Case OL 2.235''
Fired Neck Base OL 1.900''
Fired Shoulder OD 0.408''

Ray, you need to go one more step to make your measuring complete.
FL resize the cases "normally" (jamming them as far into the size die - with and/or without an expander - as a shell holder will permit) and check the case length again. I think you will find the "neck" stretch you are looking for then.

quote:

Originally posted by Nakihunter:
I thought that the neck wall got thicker and uneven, and hence the need to outer neck turn after several reloads.

I am not that experienced would like to learn....

I am no expert, but here is how i see it. With repeated firings and resizing, the brass flows forward. After 17 or more loadings, the brass will have been trimmed 3 or 4 times as it keeps getting longer after FLRS. This is using normal dies with an expander. The shoulder area will flow into the neck area, then the expander pulls or draws it forward. Brass always seems to be moving forward away from the head of the case. The only way to know for sure is take measurements with a micrometer. As for Outside Neck turning being needed on a factory rifle/ammo, i dont think its ever needed as the chambers neck area is large.The brass necks are not at there maximum allowable diameters when new. See drawings here for maximum neck/body diameters. Cartridge Drawing This might be of interest to you. How Cartridge Brass is made.