Headspace issue or not?

L

lhensler

Private
Minuteman
May 2, 2009
50
0
50
Marietta, Ohio
#1
Just recently bought a 5R .308 (new) and am reloading for it. Had pretty good results overall. Upon resizing (full length) I am getting a bright ring at the bottom above the web of the case. Upon further inspection inside the case I have detected where the ring is, the case has thinned. I have never run into this problem before, ever. Maybe I've been lucky with my past purchases.

I am not a hard core reloader but have been doing it for a long time. Anyway, from my research and knowledge I think this may be a headspace issue or I am incorrectly resizing. Am I right? As far as resizing goes I have always followed instruction from the die manufacturer (RCBS) and had no problems. My only experience reloading in the past is with a 22-250 (did varmint hunting). Just decided to get into long range shooting (as a hobby) and bought a .308 and all this happened.

I called RCBS and they said to send in five fired cases and the sizer die. Does this sound like a common problem? Anyone out there know what's going on here?
Thanks,
Larry
 
#2
Re: Headspace issue or not?

How many times have you reloaded the cases? I have seen cases that were bumped back .005" too much start showing signs of case head separation in as little as 5 reloadings.
 
#7
Re: Headspace issue or not?

I am incorrectly resizing. Am I right?"

I believe you are. Actually, if everthing else is right, and resizing is right, headspace specifications are irrelivant. What we want is for our cartridges to fit our chamber with minimum slack. Achieving that simply requires that we size the cases so the shoulder is at the same place, or just a tad further back, from it's fired lenght to the head. Excessive head set back is what causes case stretch and eventual seperation.

Use a caliper and some method of reading the (relitive) length from head to shoulder. Store bought tools and gages or 308Sako's method are equally good enough. Measure the length of a fired case to some repeatable point on the shoulder, then duplicate that length in your resized cases and you are done. (It is NOT neccessary to make them shorter, brass springback has already made the fired case a tad shorter than the chamber, right?)

Striving to resize cases to SAAMI specs, if you really want to bother with that, only makes ammo that will function and fire in any rifle ever made for that cartridge. But, doing so does make for some concern if your chamber has excess excess headspame; it will stretch cases unneccessarily and eventally makes for what you have found.

One of the prime values of reloading is to make our ammo fit OUR rifle, not everyone elses. I don't know or care what the "actual" headspace in any of my rifles is, my ammo fits and that's what I'm after.
 
#8
Re: Headspace issue or not?

A handy way to measure shoulder set back is to drill a hole in a hex nut that is a snug fit over the fired case neck. It will contact the shoulder in the same place every time and you can use it as a datum point for measuring the overall length of the brass and the hex nut. Measure a fired case and then one that has been FL resized and compare the two. If you are excessively resizing it will be easy to tell. It is also easy to tell when you bump the shoulder .002". You can drill a smaller diameter hole and use it to rest on the bullet ogive for measuring seating depth. I make these for all my bottle neck cartridges and they are handy to have around.
 
#9
Re: Headspace issue or not?

Below is a post I made over at the FAL Files on a very similar subject. Please remember that we were initially discussing loading for gas guns. Merely spinning your sizing die down until it hits the shell holder 'plus a little' may or may not be adequate. There are also a couple of good threads on this subject here - search for them.

I strongly recommend the purchase of an L.E. Wilson case gauge and either an RCBS Precision Mic or Redding Instant Indicator.
-------------------------------------------------------------

Now I'm just a simple Irish peasant, but I have been reloading since the mid-70s with no major issues. That is to say I've never blown a gun up or even had to beat the bolt open with a length of 2X4!

My understanding from doing a <span style="font-style: italic"><span style="font-weight: bold">lot</span></span> of reading on the subject and from loading and shooting a lot, is that you need to bump the shoulder back anywhere from .001" on benchrest-type bolt guns (periodically, anyway), to around .003" on gas guns like the FAL and M1A.

The instructions that come with RCBS (and other) dies that tell you to turn the sizing die down until it touches the shellholder plus a little more, are intended to allow Joe Average to make ammo that will function in his rifle, go 'BANG!' when he pulls the trigger, and more than likely hit somewhere on his target. They do that just fine.

Once one becomes concerned about things like brass life, incipient case head separation, and squeezing the last bit of available accuracy out of a given rifle/scope/shooter/ammo combination, those instructions begin to fall short.

If you fail to set the shoulder back at all, eventually that piece of brass will no longer chamber and allow the bolt to lock. You might fire it several times without bumping the shoulder back, but eventually you'll encounter problems.

Many people, especially those who follow the instructions, are probably bumping the case shoulder back farther than is absolutely necessary. They are staying within allowable tolerances of their particular chamber/sizing die combo, and their ammo functions in their rifle, but they are sizing their brass more than is absolutely necessary.

In many instances, this isn't an issue. For instance, most people only get five loads (max) out of a piece of brass for a gas gun. They discard the brass because they're (rightfully) concerned about incipient case head separation. More careful sizing (and the use of an RCBS X-die) might yield many more loads out of a piece of brass, but they're satisfied with what they're getting. And that's fine.

Others take a more detail-oriented approach to reloading. They want to insure that things are done 'right,' at least for them, and they want to minimize the variables. This is where the RCBS Precision Mic, Redding Instant Indicator, and similar tools come in. A gauge like one by Wilson will allow you to adjust your sizing die so that it produces sized brass that is 'in spec,' and will chamber and allow the bolt to close. The Precision Mic will allow you to set the sizing die to <span style="font-style: italic">exactly</span> where you want it, thus minimizing shoulder setback and increasing case life.

Is it worth the time, effort, and expense? Only you can answer that.
 
#10
Re: Headspace issue or not?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308sako</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 918v</div><div class="ubbcode-body">I prefer to use a Redding competition shellholders. That way you know you are bumping .002" from zero. </div></div>

The problem with this is without measuring the actual amount of setback... what the heck do you have? </div></div>

Fire the cases enough times that they will not chamber(or at least until they take a lot of effort) and start off with the -.010" shell holder and resize the case. If they still will not chamber then go to the -.008" shell holder and so on until they do fit. The most you will ever get will be .002" setback if you do it correctly.
 
#12
Re: Headspace issue or not?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dmg264</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308sako</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 918v</div><div class="ubbcode-body">I prefer to use a Redding competition shellholders. That way you know you are bumping .002" from zero. </div></div>

The problem with this is without measuring the actual amount of setback... what the heck do you have? </div></div>

Fire the cases enough times that they will not chamber(or at least until they take a lot of effort) and start off with the -.010" shell holder and resize the case. If they still will not chamber then go to the -.008" shell holder and so on until they do fit. The most you will ever get will be .002" setback if you do it correctly. </div></div>

Yeah! What he said.
 
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