PPC Cases, want to know more about them!

[JRB]

As I understand it, the .262 neck came about from the combination of the thickness that Sako .220 Russian cases had to be turned to to clean up, and the desired clearance between chambers and loaded rounds. Later, when Lapua cases became available, the .262 neck has continued because reamers and bushings would have had to be replaced for a different size, and the existing size seemed to be working pretty well, which minimized the incentive to make a change.

A few years back, some bright fellow, who was an experimenter by nature and well enough funded to disregard the cost of a reamer and a couple of bushings looked at the situation and decided to try a larger neck diameter, given that the Lapua brass would clean up at a greater thickness. The .269 neck chamber was the result, and by all accounts that I have read, it has shot as well as .262, with the added advantages of being a little easier to turn for, and greater resistance to being dented when used in conjunction with an ejector. I have also read of .261, .263, and 265 chambers, but these seem to have gotten less attention. To my knowledge, none have offered any particular accuracy or case life advantage (or disadvantage).

At the present time, if I were ordering a new reamer, there are a couple of factors that might cause me to change from the .262 neck that my current one has.

One is the previously mentioned ejector. A thicker neck would undoubtedly be more dent resistant in that application.

The other reason would be to be able to go back to the neck thickness that I had before switching to a larger neck to chamber clearance. The clearance that I used to use was around .0015 +-and the current clearance that I use is closer to .003. It has seemed to me that 133 likes about as much neck tension as can be managed with necks turned for more traditional clearances for a .262 neck, and that thinner necks seem to require slightly less force to seat bullets. Adjusting for this difference would only require increasing my chamber neck diameter to .2635 or .264.

On the other hand, we are blessed with a couple of new powders that seem to be producing very good results with slightly less neck tension than 133 likes, so I have taken a wait and see attitude.

As far as the longevity of cases is concerned, I have not had much of an issue that way, I don't remember ever having a neck come off a case, but of course mere case survival is not the only, or most important issue.

One thing that I have been careful about, that may have contributed to my case necks staying attached, is the radius where cutters' leading angles meet that part of the edge that is near to parallel with the turning mandrel. I have seen cutters that were a little too sharp for my taste at the apex of this angle, and have remedied this by a small amount of stoning. Also, a friend has a turner, that does not seem to have any significant leading angle, which causes the leading corner to dig into the shoulder. I would not have this configuration for my use, but he is only taking a light cleanup cut for a close neck chambered BR, so it has not been a big deal.

For competition, it is obvious that if one can shoot smaller aggs with fresh brass, then worrying about getting the last gasp out of cases would seem to be false economy, given all the other costs of shooting matches.....but I think that this is a matter that should require some testing to determine. One issue in this would seem to be how a particular shooter tunes. Not all good shooters take the same approach to bullet seating depth, choose to be at the same node, use the same powder, or have chamber bullet combinations that have the same length of bullet shank in their cases necks. There factors may combine in different ways which result in differences in how important having fresh brass is.....I think.

Of course you can always pick some winning shooter and simply copy what he does, which, after all, may be the simplest approach, particularly if your primary goal is to develop an effective procedure with the least delay.

Boyd,
Some good tips and advise, discussion on some history of the .262" neck.
Just out of interest what did the Sako brass measure before it was neck turned?
I somewhat believe that many of the misconseptions about turning necks, in the early days, was compounded by the lack of having the right tools for the job, or lack there of.
I have been turning necks for over 15 yrs, and only recently have been able to produce quality necks.
It is clear that neck tesion and or variations, are a constant focus for the BR shooter, How do you control variations in this?
Is this ultimately effecting the case grip on the bullet? or release pressure?
Good Shooting !
Jim

 

[Boyd Allen]

Oh I wish that I had all of the answers to your questions. First of all, I came into the game too late to be using Sako brass, someone gave me a few, but I can't find them at the moment. I guess that I am lucky tool wise, I have always had stuff that could be made to do a good job, if you paid attention to the right details, but I claim no special knowledge on the subject. Given that up to now, we seem to have needed all of the bullet pull that could be managed, and that even something less than a full annealing of necks is likely to reduce that pull, all that we can, or could have done, it to sort by either feel, or use some sort of gauge when seating bullets, so that cases can be sorted into groups that have required similar bullet seating force.

As to what is really going on, I think that to a degree, that depends on your choice of seating depth, and how much of the bullet is within the grasp of the case neck.

When a flat base bullet is seated, a sort of step is formed in the case's neck, at the bullets base. There is also the friction of the neck caused by its elasticity on that portion of the bullet that is gripped by the case neck. When we change to a die or bushing that sizes necks so that there is a greater difference between the sized neck, and the diameter of the neck over the bullets pressure ring, we increase the elastic grip up to the point where the bullet simply acts as an expander, and the neck is expanded beyond its elastic limit by the bullet as it is seated.

On the other hand, creating a larger step at the back of the bullet would seem to increase the seated bullet's resistance to being pushed farther into the case neck, lengthening the jam (maximum length to which a bullet may be seated without being pushed into the neck as the round is chambered) and with that the amount of force required to start the bullet down the barrel. I think that it becomes slightly harder to start because it is more tightly wedged into the leade angle. So even if one argues that bullet pull levels out at some point, there may be additional bullet start pressure created by the increased step dimension. Much of this is nothing but my specuilaton, but I thought that in the spirit of the discussion, and in light of your questions, that there would be little harm in sharing it.

 

[JRB]

Boyd,
A most helpful reply,
This is facinating stuff and i have been thinking about some of these things for a while.
it appears that it is very hard to know the true effects of bullet seating with neck tension, apart from that it changes the bullet release in some way. But how!
I am still uncertain of the process to achieve this harmony.
I have used the 'seating lenght' tuning process in Tony's book, with good success, but still canot see, any change in neck tension with any effect. Not knowing what to look for. or not having the ability?
I then must have to assume that this is very fine tuning, done after seating depth is obtained?
Good Shooting!
Jim

 

[JRB]

Another observation on neck thickness, FWIW. In 2003 I bought a bunch of reamers and gages from Ferris Pindell. One of the first things I discovered was the reamers an gages were all 266 neck. I called Ferris and ask him about this and why the 266 neck now and the 262 neck earlier. His reply about the why of the 266 neck was, as Boyd said above, the brass they had at that time required a 262 neck to clean up.

I have shot the 266 neck in all of the 3 designs of Ferris PPC's based on the reamers he was using.
I started using the 266 neck in 2003 and shot it entirely till the 2012 season. True, the thicker neck does give slightly more neck tension than the 262 neck and V133 likes that.

The bad thing I found out and it took me a while to actually determine was that in using a thicker neck, over time, and as the brass work hardens, not all case necks, even from the same box, work harden the same. This, to me, shows that neck tension can not be controlled as well with the thicker necks, IF, the cases are fired over about 10-15 times.

As to the V133 powder and Ferris's cartridges with the 266 necks, I did not find any V133 in his loading room when Jim Carmichel and I inventoried his estate in 2011. This does not mean Ferris did not shoot V133. Jim Pickrell would know much better than us. By the time we did the inventory for his wife Jim Pickrell had already sold of a lot of the perishables for her.

Jerry,
Thank you for your reply.
I was wondering about these things, from here anyway, it appears that the .262" neck still has a strong following, and this makes alot of sense, beyond the valid points previously made.
My brass having a .270" and neck, having about .012" of neck wall thickness.
A case with a .262" neck, having about a .008" neck wall thickness gives a reduction in wall thickness of about 1/3, but i bet that in seating a bullet, the 'feel', available is not 1/3 better with the thinner case.
There is a lot of discussoin on the 'feel' in relation to available neck tension and seating of bullets, i gather this directly relates to case hardness?
What problems did you encounter with a thicker necks?
what does this 'tension' variation show on the target?
Good Shooting!
Jim

 

[JerrySharrett]

Jerry,
Thank you for your reply.
IWhat problems did you encounter with a thicker necks?
what does this 'tension' variation show on the target?
Good Shooting!
Jim

I classify seating pressure by the following;
Light=Using a Wilson type seater I can seat a bullet with just thumb pressure
Medium=I need to use the heel of my hand to seat a bullet
Heavy=I need an arbor press to seat a bullet

What problems did I encounter? Not much other than case necks seemed to vary in hardness after a few reloadings

Does this tension show up on the target, probably yes, with some powders, definite yes with others.

 

[JRB]

Given that up to now, we seem to have needed all of the bullet pull that could be managed, and that even something less than a full annealing of necks is likely to reduce that pull, all that we can, or could have done, it to sort by either feel, or use some sort of gauge when seating bullets, so that cases can be sorted into groups that have required similar bullet seating force.

Can you shed some light on, Bullet pull?
Have not heard that term before
Jim

 

[JRB]

I have shot the 266 neck in all of the 3 designs of Ferris PPC's based on the reamers he was using.
I started using the 266 neck in 2003 and shot it entirely till the 2012 season. True, the thicker neck does give slightly more neck tension than the 262 neck and V133 likes that.

The bad thing I found out and it took me a while to actually determine was that in using a thicker neck, over time, and as the brass work hardens, not all case necks, even from the same box, work harden the same. This, to me, shows that neck tension can not be controlled as well with the thicker necks, IF, the cases are fired over about 10-15 times.

As this case hardening occurs and variations become apparent, can anything be done to 'service' the cases, like annealing?
Good Shooting!
Jim

 

[JRB]

I classify seating pressure by the following;
Light=Using a Wilson type seater I can seat a bullet with just thumb pressure
Medium=I need to use the heel of my hand to seat a bullet
Heavy=I need an arbor press to seat a bullet

What problems did I encounter? Not much other than case necks seemed to vary in hardness after a few reloadings

Does this tension show up on the target, probably yes, with some powders, definite yes with others.

Jerry,
If you had some cases from each extreme, would you expect to see verticle on your target?
Jim

 

[Boyd Allen]

By bullet pull I mean the amount of force it would take to start the bullet moving in the direction that it is propelled when the round is fired, without considering engagement of the rifling. The only practical way that we have to gauge this, in a way that can be applied as we are loading (NDT?), is by the force that it takes to seat bullets.
My reason for using the term bullet pull is that neck tension is often used to refer to the difference in diameters of a sized neck and that same neck with a bullet seated, measured over the pressure ring, if it has one. The problem with using this difference in diameters is that it does not take the hardness of the brass into account. You could have two cases that had the same sized neck diameter, and diameter over seated bullet, but differences in friction between the bullets and the necks, and the hardness of the brass, could make a major difference in how much pressure it would take to seat the bullets. The assumption is that the pressure required to start the bullet moving out of the neck is proportional to the force it took to seat it. No, I don't have any data proving this. (Did you get all of that? There will be a quiz on Monday.)

 

[alinwa]

When I measured bullet pull I found that there is not a direct correlation between seating force and pull.

JMO

al

 

[Boyd Allen]

Since assumption falls well below testing, tell us what you found....if you don't mind.

 

[alinwa]

Short-short, I won't get into poundages and such.

When testing annealed necks bullet pull was essentially two settings, 'light' and 'light/medium' no matter what you did with bushing sizes. One could use a .004-under bushing and get the same pull as a .002 under, call it "plateau'd." I call it "like lead," annealed brass yields at very low tensile load exhibiting very little springback. For this reason many choose to anneal. But you cannot ever achieve high neck tension, nor even "moderately high." (these are just terms I use)

When testing un-annealed brass things get interesting. I won't go into all the differences because they are many but suffice it to say you can "chase" the yield curve up the scale as the brass workhardens and that it'll climb up-up-up-YIELD- lower-up-up-up

Like Jerry I found times where the brass became inconsistent. Beyond this area is where the cases "get good" IMO.

I've stated before and I'll state again, "cases don't really start shooting until they've been fired 20 times."

Most real shooters will disagree with this statement, some strongly. Most chuck their cases before 20times.

I'm not promoting anything here, nor trying to convince anyone of anything.

PLEASE all y'all, TEST THIS STUFF. T'aint hard to set up a collet puller.

al

 

[Boyd Allen]

Just an idea, if perchance one used a die with an expander that was larger than normal, that would expand a neck to the diameter that it would be after firing, and a "normal" sized bushing, could he work a case that had become inconsistent, and not yet become consistent again, by running it in and out of the die, simulating repeated firings and sizings? Yes, I know, outer limit stuff.

 

[alinwa]

Just an idea, if perchance one used a die with an expander that was larger than normal, that would expand a neck to the diameter that it would be after firing, and a "normal" sized bushing, could he work a case that had become inconsistent, and not yet become consistent again, by running it in and out of the die, simulating repeated firings and sizings? Yes, I know, outer limit stuff.

IMO no.

IME running an expander thru drags the brass around much more than neck bushings do, which "stands to reason" when you look at the direction it's working. I simply cannot find a valid reason to let an expander touch a case once it's been fired. And I've got expanders of all shapes, sizes, materials and hardnesses.


BTW, when experimenting with bullet pull one will SOON see a relationship between neck clearance and consistency. In my experience moving necks more than .003, maybe .004, (effective) TOTAL will result in inconsistencies.

That said, I don't think bullet pull is much of an issue.

Really.

bear with me

hear me out, clear out.


I'ma' go WAYYYY out on a creaky limb here, prolly get my donkey handed to me......with both hands.

In the biz there's a tuning system that uses "seating depth and neck tension" to get all the bullets in a small hole. In other words, you "find a node" and then you "fine tune with seating depth and neck tension."

It's a proven system.

ya don't mess with a proven system.

(Well, I do, but you know...)

I found "playing with seating depth and neck tension" to be confusing. I also found via testing that they're interrelated, increasing neck tension a thou may well give the same result as going deeper into the lands for instance. In other words, THEY PLAY OFF EACH OTHER.

IMO

Now......

I'm a simple guy.

K.I.S.S. thine ame is al.

al, thine aim is simplicity, fewer variables.

I can't balance a scale by throwing down weights on both sides at the same time.

So I cut it in half. Bada'BOOM, one bushing,

ONE variable,

gone.






Once I'd concluded that they feed off each other, I locked down the neck tension and worked with just seating depth. FOR ME, it works....I submit that if you throw "playing with neck tension" out the window and fiddle only with seating depth you can get the same results. No, you don't ignore tension, you just keep it consistent and forget it.


i'll be interested in what others think

al

 

[Boyd Allen]

Al,
I wasn't writing about anything else. To recap, cases start out at a given level of consistency (of seating force). They are fired a number of times and become less uniform in that respect. They are fired more times and their consistency improves. During those firings on the way to the return of consistency, their necks are expanded to the limit that the chamber allows, and reduced to the dimension that the bushing dictates, several times. All that I was suggesting was that one could use other means to do that expanding and reducing. As far as expander drag goes, that is why they make various kinds of slick stuff, with which the inside of the necks being processed might be lubricated, to minimize the pull. If a normal firing leaves a neck at .001 below chamber neck diameter, and sizing reduces it to say .004 to .005 less than that, before bullets are seated, then necks are normally worked by that difference, every time that a case is fired and sized. If it is this working that causes cases seating force to become more uniform, why could we not just do that expanding and reducing by mechanical means? Would the necks know the difference? If it turns out that that would work, would this not be a good thing? Del Bishop once told me that it was his, and a friend's practice to do this sort of thing to unturned or fire formed cases (that were destined to become 6PPCs) using a one piece die that had a larger than normal neck ID, and that had its expander in place. He said that this conditioning of perhaps half a dozen cycles would improve the interiors of the cases, leveling them out to a more cylindrical shape, before they were turned. As you know, this would have also caused some work hardening. What I am describing is similar, but for a slightly different purpose.
Boyd

 

[Joe Woosman]

Removed misleading info.....

 

[Joe Woosman]

If it is this working that causes cases seating force to become more uniform, why could we not just do that expanding and reducing by mechanical means? Would the necks know the difference?

Boyd,
In my experience, working the necks with expanders and bushings only can reduce the consistency of brass strength. Yes it will harden as well as iron out surfaces. But they have no control over where the brass yields. You just may be hardening one line along the neck rather than the entire circumference of the neck.

I once tested the speed at which expanding was done. With a machine using controlled velocities, I found the faster I could expand brass necks with the least amount of friction was the best case for uniformity. This would support others claims that cases fired multiple times may become "better". A work hardening would take place with less of the inconsistencies expanders and bushings can produce.

Using new brass all the time will provide consistency. Using older well maintained brass could possibly be better, but only if they are not overworked by the dies.

 

[alinwa]

OK Boyd, next answer (opinion)...... "inertia."

I don't know another way to describe it, but working a neck via firing the case VS working the neck with a mandrel produces two distinctly different effects. JUST in regards to differential circumferential hardening using a mandrel makes it more uneven while firing the case evens it out.

In the same way that blowing necks out while fireforming gives better, more consistent results than expandering necks does. Reworking a neck mechanically is like picking a scab, it makes the bad spots worse. Massaging the necks down and blowing them back out is like applying a nice ointment, it evens the necks out.

I don't know how else to put it.

opinionby


al

 

[alinwa]

YES!!! You got it Al. They DO feed off each other. In fact, they DO exactly the same thing. They both adjust the timing a little. That's it. Nothing majical. No pixie dust from the benchrest gods sprinkled on anything.

I'll give you this to chew on... What happens when the primer goes bang - but just before the powder lights up? A shock wave of pressure is sent through the powder charge hitting the base of the bullet. The neck tension and seating depth is going to determine how far the bullet is seated into the lands. The tighter the neck tension, the less force is transfered to the bullet reducing how far that bullet is seated into the barrel. The further off the lands the bullet is seated, the greater the head start the bullet has and the further it will seat into the barrel.

From there the powder charge takes over and this is why it appears we have two different areas important to tune. The forces that affect the initial seating of the bullet by the primer, and the powder burn curve. It stands to reason these two timing curves work somewhat independently of each other, but in combination provide better or worse bullet/barrel harmonic timing. This is why both must be considered to achieve optimum accuracy.

I'll leave it at that for now before someone calls for my beheading.

OK, just between you an me One of my "methods" is to check for "sufficient" neck tension thusly...... I first load up some primed empties and pop them in the chamber, "did the bullet move?" I then fill the cases about 7/8 full with COW and pop a couple more.... "did the bullet move?"

When the answer is "no," plus a little more, I've got "enough" neck tension.

Now the hard part is getting it to keep.

al

 

[Boyd Allen]

Just to clarify, what I described was to be done with "experienced" neck turned PPC brass. What I described that Del did, was done before any turning or fire forming, and if you remember how well Del shot, I think that we can agree that there was not much wrong with his brass. One more little tidbit...he turned all of his brass using hand power. He never told me the exact reason, but there was not doubt that he believed that there was some advantage to doing so. For those who did not know him, Del was a highly respected bullet maker and shooter, with a lot of experience behind him, who did not shrink from investing in ideas that might improve performance. He lived in the state of Washington and I am lucky to have known him.