excessive headspace

Drover,
Yes, that is what I meant. You should see a fired case that has no bright line, and if you are careful, and neck size (at the end of the neck, just enough to barely hold a bullet) one of those cases and fire it with a stout load, you will have created a reference case to use when using a caliper attachment to set your FL die. (Assuming all this works, mark and save this case.)You should decap the case with a punch so that a primer crater will not spoil your measurement, and do the same thing to the case that you use to test your die setting, as you adjust it down. I like a .001 to .002 bump, but variation in brass hardness, even with new brass may make tight cases if you happen to set up on one of the softer ones in a batch. Once you have fire formed the shoulder to the correct position, and if you set your die correctly, there should be no more problems with those cases. (hopefully) Let us know what happens.
 
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Boyd,

Got it!! I will give this a try.

Thanks so much for the tip - I will post results as soon as I do it.

drover
 
Boyd,

You have the answer. I could not stand it, cold or not, I had to give it a try, luckily I can go on my deck and shoot and I have a hillside full of rocks about 150 yds away.

The next pictures are the case after resizing the 6mm expanded neck back down to 224 to where there was a slight resistance when closing the bolt - the juncture where the two different necks meet is quite clear.
DSC07236.jpg


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I followed your instructions and on the first firing I did not get the shiny ring but I could see a little metal stress in the usual place using a magnifiying glass- there is a very slight ring but nothing like I have experienced in the past..

picture after first firing with snug 6mm - 22/250 juncture
DSC07237.jpg



the next pictures are of the case after 15 firings and neck sized only - it is beginning to get hard to chamber at this point but the primer pocket is still snug.
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DSC07238.jpg


I am more than satisified that your suggestion has taken care of the problem. I intend to size the remaining 99 pieces of brass up to 6mm and then back down to a snug chamering 224 neck, if the piece that I have fired 15 times is representative I should be able to take the remaining useful life out of this barrel with those and then have it rebarreled and correctly chambered.

Question - In thinking about what is going on here what I am seeing is that the headspace as measured from the base of the cartridge to the base of the shoulder is correct. However the base of the shoulder to the neck has an issue of to much room and when the cartridge is fired the loose shoulder/neck is letting the case go forward and then the case expands back creating a stretch in the case, which weakens it and causes premature failure. What I am doing by creating the false neck is in effect keeping the neck/shoulder area from going forward and doing this. I have a hard time envisioning what happened, when the barrel was chambered, to create this problem but this takes care of it.

If I am all wet in my reasoning please try to explain to me just exactly what is happening.

I do intend to F/L resize the case and then continue using it until I see impending failure. At this point I suspect that I can get a few more loadings out of it because the metal stress has not increased appreciably and the primer pocket is still snug. For this exercise I used my standard load of 35.5 gr H4895 / Fed primers/ Winchester cases / 50 gr Nosler BT.

I truly appreciate everyones help in solving this issue, the knowledge here, and the willingness to share it, still astounds me.

Thanks - drover
 
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Headspace is measured with the proper gauges, go and no go. The bolt should close on the first, but not on the second. On a SAAMI drawing the headspace is not given as from the point of the shoulder but from a circle of a given diameter that is on the flat of the shoulder. If you are doing anything but using the proper gauges, you are simply comparing cases, new, fired, and sized by using an attachment to a dial caliper, or some other type, to measure off of the flat of the shoulder to the base of the case. This is fine for reloading, but if you want to know if your chambers true headspace is correct either take it to someone with the correct equipment, or get your own. Those are the options. Since it is so cold outside, why don't you section one of the cases that you just fired, and post a picture after doing some measuring, if there is any thinning. Let us know what happened. We had it really rough today, as the sun goes down, it is 56 and was sunny. Burrr ;-)
 
I didn't read all the above posts. But, if your concern is for limited brass life within one gun and one group of brass, let the chamber tell you how your resizing is going. Strip the firing mechanism from the bolt. Forget the Lee neck sizer. Full length size the cases to where there is a slight drag in just the last approx 1/2" of bolt closing. Remember, this is a standard Remington 700 with the spring ejector and that spring will bias the feeling you would get with a non spring ejector bolt.

If you are still experiencing reduced case life your chamber may be oversized in body diameter, if this is the situation, there really isn't much help other than rechambering.

I've written the above many times on this forum and used to get yelled at for suggesting this process but I notice Tony Boyer, in his book, suggests the same method......so there!!!
 
Boyd,

Thanks again for the explanation of how headspace is determined, you cleared up a misconception I had about how it is measured.

When I get a chance to be in Boise or Idaho Falls I will try to find someone with a set of gauges, although now that this is going to fix the issue it is pretty much irrelevant.

I will fire a new piece of brass and section it to see what it looks like and will post a picture - this will be sometime over the week-end, I am tied up for the next couple of days.

drover
 
Or you could call David Kiff PTG in White City OR and just order a "Go" and a "NO GO", they are about 27 bucks each. The other thing is... By the time you have all this figured out, you'll have burned out your excessivly long headspaced barrel. The next job is to have a new barrel cut, at the correct headspace, and all this will be just a learning process from the past.

Paul
 
JerrySharrett said:
I didn't read all the above posts. But, if your concern is for limited brass life within one gun and one group of brass, let the chamber tell you how your resizing is going. Strip the firing mechanism from the bolt. Forget the Lee neck sizer. Full length size the cases to where there is a slight drag in just the last approx 1/2" of bolt closing. Remember, this is a standard Remington 700 with the spring ejector and that spring will bias the feeling you would get with a non spring ejector bolt.

If you are still experiencing reduced case life your chamber may be oversized in body diameter, if this is the situation, there really isn't much help other than rechambering.

I've written the above many times on this forum and used to get yelled at for suggesting this process but I notice Tony Boyer, in his book, suggests the same method......so there!!!
Click to expand...

There is a difference Jerry :)

Anyone quoting Tony Boyer must take his quote in context IMO, Tony's quote is referring to a very specific chambering as done by a World Class Gunsmith under controlled conditions and using a resizing die MADE SPECIFICALLY for this particular chambering. Not for this chambering at large, 6PPC, because IT TOO can be had in a variety of configurations...... but for this particular iteration of the 6PPC. In the world of 22-250's there are possibilities for great variances, variances which simply do not apply to Tony's world or Tony's quote. One of them, the really large one as you noted above, is that 22-250 chambers vary in diameter and are severely tapered. Factory 22-250's vary within a range of .005 to .007 or even .010 diameter.

As do factory produced dies. And the problem as stated would result from the chamber being TOO SMALL for the resize die, not too large as you stated. One answer would be to polish the chamber out larger.

I think this is an important distinction.

This is also the problem inherent to the old "Bump Die" that folks used to tout.... the die cut with the chambering reamer. The only way to make a "Bump Die" work is to cut a clean die and wallow your chambers!

In My Opinion it is rash to assume that the "feel" generated by sizing with a factory die coupled with a factory chamber indicates anything about shoulder setback.

So this is why you've been yelled at :) so there!

al
 
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drover: Those older Varmint Specials were good shooting guns...the newer offerings by Big Green don't hold a candle to 'em. The final piece of your puzzle can be seen in your last pics:

Distal to the 'shiny ring', the fired case is markedly smaller than the chamber....even when taking into account the unsupported area of the case in a 700 action.

Lapua 22-250 cases measure .470 at the very proximal edge of the extractor groove and about .4685-ish at the area where your 'ring' occurs. They would likely be a great fit for your chamber. The Lapua cases, combined with a good f.l. bushing die (like the Redding Type S) and a tool to measure how much you're setting the shoulder back, and you'll be in great shape.

The only thing I'd add to Boyd's advice is to lightly oil the cases for the initial firing. This allows the case to better conform to the chamber by reducing the tendancy for a dry case to 'stick' to the chamber as the pressure increases during firing...which makes the back end of the case stretch rearward until it meets the boltface. This may be another reason why you're getting such pronounced stretch marks, initially. If you've got a virgin piece of brass, try it and see if it makes any diffference.

Really, whether the headspace is out of spec. doesn't make any difference. If you can properly f-form cases and the die is set to work with those dimensions from then on, life will be good. :D

Just how I'd approach it here in icy South Dakota.....:) -Al
 
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