case separation

[Ketosan]

Speedgun,
Another option for measuring headspace is the RCBS Precision Mic: http://www.midwayusa.com/find?userSearchQuery=rcbs+precision+mic
At Midway they sell for around $53.00 and they have em for 25-06.
I've used them for years and found them to be quite accurate and very useful for setting sizing dies. Recently bought 100 pieces of Norma 308 brass--after checking the headspace with the Precision Mic, found the brass had excessive headspace--averaged around -.022--which is quite rare for new Norma brass. So wanting a second opinion sent the brass to a friend with very sophisticated measuring equipment and my initial readings were confirmed. Then sent the brass to Norma in Sweden and again my readings were confirmed. Oh and Midway was more than happy to refund my money and shipping costs!!!!!
As an added bonus the Precision Mic can be used to measure and set seating depth--
And it is very easy to use!!!

 

[Shynloco]

I also suggest using a Wilson case gage. The Hornady tool is OK but the Wilson is easier to use, IMO.

The Wilson gauge, or the Hornady tool will tell you nothing that will solve your problem.

You need to adjust your die so there is no space when the sized case is chambered... there is no magic tool for that.

IMHO, what Catshooter says is absolutely correct. About 4 years ago, I had a 22-250 that had the same problem that the OP described. Could only get 4 reloads out of casings until head separation started or happened. And I would NOT recommend pushing the envelope and dump the brass that displays the signs of head separation as once it happens inside your chamber, it'll take some expertise and proper tool to remove the front portion of the casing. I tried all sorts of things like adjusting the die, various headspace measuring tools and even had two experienced Gunsmiths measure the chamber for headpsace...problem persisted. Finally gave up and changed the caliber and had her rechambered. Problem went away. Whether it was just a bad chamber or me, can't say. But now the rifles shoots just fine as a 6.5BR and I have no signs that the previous caliber displayed.

Alex

 

[justpassinthru]

I also suggest using a Wilson case gage. The Hornady tool is OK but the Wilson is easier to use, IMO.

The Wilson gauge, or the Hornady tool will tell you nothing that will solve your problem.

The OP is having case head separation due to either his die pushing the shoulder back too far or the headspace on his rifle being out of SAAMI specs.
Either of these conditions is something the Wilson gauge will clearly show.
Sure, your method will work but that doesn't mean that LE Wilsons method will not.

 

[CatShooter]

Recently bought 100 pieces of Norma 308 brass--after checking the headspace with the Precision Mic, found the brass had excessive headspace--averaged around -.022--which is quite rare for new Norma brass. So wanting a second opinion sent the brass to a friend with very sophisticated measuring equipment and my initial readings were confirmed. Then sent the brass to Norma in Sweden and again my readings were confirmed.

That is a lot of effort for a simple (and common) problem that is easy to resolve.

I also suggest using a Wilson case gage. The Hornady tool is OK but the Wilson is easier to use, IMO.

The Wilson gauge, or the Hornady tool will tell you nothing that will solve your problem.

You need to adjust your die so there is no space when the sized case is chambered... there is no magic tool for that.

IMHO, what CatShooter says is absolutely correct. About 4 years ago, I had a 22-250 that had the same problem that the OP described. Could only get 4 reloads out of casings until head separation started or happened. And I would NOT recommend pushing the envelope and dump the brass that displays the signs of head separation as once it happens inside your chamber, it'll take some expertise and proper tool to remove the front portion of the casing. I tried all sorts of things like adjusting the die, various headspace measuring tools and even had two experienced Gunsmiths measure the chamber for headspace...problem persisted. Finally gave up and changed the caliber and had her rechambered. Problem went away. Whether it was just a bad chamber or me, can't say. But now the rifles shoots just fine as a 6.5BR and I have no signs that the previous caliber displayed.

Alex

Alex... badd puppy!!

Anytime you have a case that is shorter than the rifle's chamber, you invite head separations.

95% of the time, this is the situation when you first fire a case in a rifle - cases are made smaller than chambers so you can buy a box of brass or ammunition and it will fit any rifle you have.

There can be as much as ~15 thou of empty "airspace" between the bolt face and the case head, and it is still in "spec".

When you fire that case in a dry chamber, the case will stretch to fill the chamber, and in the process, weaken the junction of the body and the head (the web)... which can never be repaired.

This damage can be avoided, but even when it is not, what happens after that is YOUR fault.

The minimum length of a case should be, is when a case (or round) is chambered with a stripped bolt, the bolt handle will drop half way down of it's own weight, and require the slightest nudge with a finger to fully close it. most benchrest rifles are set up this way so the rifle does not "roll" in the sand bags. A case should be NO SHORTER, but it can be longer and require some effort to close (if you are not shooting bench).

If this situation is met, the cases will NOT stretch, and you will NOT have head separations, no matter what the dimensions of your chamber.

 

[BoydAllen]

I completely disagree with the idea that gauges have no place in setting FL dies. IMO they are central to getting it right. Using bolt feel to evaluate a die is OK, but using it to set bump assumes that the die is small enough in inside diameter relative to the chamber, which it may not be. All in all, arguing against measuring tools seems to me to be silly. From my perspective it would be like arguing against the use of dial calipers or micrometers, or for that matter tape measures.

Decades back, when the Stoney Point "headspace gauge" that Hornady now sells came out, and I had only recently become aware of the issue of setting FL dies properly, I had a Wilson gauge, and although it had been the sole tool available for such work for a long time, decided that the Stoney Point too would be more economical than buying a Wilson gauge for each caliber that my expanding rifle collection would require. Once I had the set in hand, I discovered how much better, and more precise it was than referencing the step on the end of the Wilson gauge, and have counted on it for useful information ever since. One thing that it allows me to do is to track the growth of case "headspace" from first firing, so that I can determine when that dimension stops increasing to extablish the dimension from which I reference shoulder bump settings. I usually do this for each new rifle or barrel, with one case that I load and fire repeatedly during a single range session.

Another use has been to become better acquainted with how cases behave when light loads are used ("headspace" of rimless cases will shorten) and how they change as FL dies are adjusted down to their final setting. Both of these things have materially increased my understanding of what is taking place with my brass during firing and sizing.

One tip for those new to this area that is worth mentioning is that it takes several firings for a case to reach its maximum "headspace" and if you are setting a FL die and only have once fired brass to work with, setting the die so that the case measures the same as after it was fired seems to me to be the best method, given that at that point it does not need additional clearance at the shoulder.

For those that like to buy new toys from time to time, and find that picking off thousandths to arrive at a precise die setting is a bit of a pain (given that each requires 1/71 of a revolution of the die) here is a link to a short video that demonstrates how the PMA Tool Micro Die Adjuster works. My apologies for the amateur video quality, or rather lack thereof. It was my first. https://www.youtube.com/watch?v=iR7iixACxR4

 

[CatShooter]

I also suggest using a Wilson case gage. The Hornady tool is OK but the Wilson is easier to use, IMO.

The Wilson gauge, or the Hornady tool will tell you nothing that will solve your problem.

The OP is having case head separation due to either his die pushing the shoulder back too far or the headspace on his rifle being out of SAAMI specs.
Either of these conditions is something the Wilson gauge will clearly show.
Sure, your method will work but that doesn't mean that LE Wilsons method will not.

His chamber can be max, and still in SAAMI spec... his sizing die will be SAAMI min or a few thou less (if it is made properly), so if he FL sizes his cases 5 times, his cases will stretch 50 to 80 thou... and they will separate, and the Wilson gauge will keep telling him that everything is fine .

Wilson (and ALL drop-in case gauges) are too crude for careful loading.

 

[BoydAllen]

"Wilson (and ALL drop-in case gauges) are to crude for careful loading." True.

 

[fredo]

As a beginner reloader, I found favor with using RCBS Case Mic gauges for setting my FL die to resize brass for semi auto ARs. Quick, easy & basically idiot-proof method for getting a measurement off the fired case shoulder. Set the FL die to bump -.004-5" for semi-auto, to insure reliable feed/function without over-sizing & creating excess headspace...

For bolt gun, I do as described above & let the rifle be my gauge. The tactile feel of the bolt just closing on a sized case works fine. Set the lock ring on the die & rock on...

 

['Freak]

The only way headspace can be changed is by you moving the size die either in closer to or out away from the shell holder so that more or less of the case’s length gets shoved up into and is acted on by the size die. You’re adjusting the die so it’ll change the sized case’s base to shoulder datum length to get the kind of fit you want your cases to have inside that one particular chamber. Unless inadequate lubrication over too many cycles that can come from running cases you sized for an interference fit results in excessive wear of the locking lug engagement surfaces, the length dimension from the bolt face to the chamber’s shoulder datum is never going to be much if any different from what is was made to be by whoever was driving the reamer when that particular chamber was cut.

 

[Webster]

What's your opinion. Drop in headspace gauges measure case head face to cone. Isn't bolt face to cone the number you need. Impossible measurement. I use Tony Boyle's method. It uses the your dimensions of bolt face location and your chamber.

 

['Freak]

BigEd has posted, w/pics, the simplest, easiest method of checking how much clearance remains between the base of fired brass and the bolt face that I’ve seen:

Partially seat a spent primer so leaving it standing proud, stick it in the chamber and gently close the bolt.

The bolt face shoves on the spent primer so pushing the case forward until the case shoulder butts against the chamber’s shoulder, and then it’ll seat the spent primer deeper though still leaving it standing proud by an amount equal to the clearance that’s left between the bolt face and the base of the fired case.

Measure the amount the spent primer is left standing proud and add that to the case base to shoulder datum dimension, and that’ll be plenty close enough to the bolt face to chamber shoulder datum dimension.

 

[CatShooter]

The only way headspace can be changed is by you moving the size die either in closer to or out away from the shell holder so that more or less of the case’s length gets shoved up into and is acted on by the size die. You’re adjusting the die so it’ll change the sized case’s base to shoulder datum length to get the kind of fit you want your cases to have inside that one particular chamber. Unless inadequate lubrication over too many cycles that can come from running cases you sized for an interference fit results in excessive wear of the locking lug engagement surfaces, the length dimension from the bolt face to the chamber’s shoulder datum is never going to be much if any different from what is was made to be by whoever was driving the reamer when that particular chamber was cut.

One of my Remingtons is now on it's 6th barrel (since 1975)... somewhere around 15,000 rounds. And other than light oil on the lugs, it has never fussed over - it has not worn a bit.

This is not an issue in headspace/head separation problems.

 

['Freak]

Tight to the point that closing the bolt wipes the engagement surfaces free of lubricant combined with inadequate bolt maintenance is what will result in excessive wear. A consistently tight fit via consistently, strictly maintained brass would be the work around necessary to maintain consistency in the case fit’s effect on harmonics and so harmonics’ affect on how the thing shoots. Sure, tight can be made to work.

 

[CatShooter]

Tight to the point that closing the bolt wipes the engagement surfaces free of lubricant combined with inadequate bolt maintenance is what will result in excessive wear. A consistently tight fit via consistently, strictly maintained brass would be the work around necessary to maintain consistency in the case fit’s effect on harmonics and so harmonics’ affect on how the thing shoots. Sure, tight can be made to work.

Huh?? Harmonics??

It makes no sense... none of it makes any sense.

Since almost ALL match rifles are set up so the handle on a stripped bolt will drop halfway down on a case (which means that there is zero clearance), then you are saying that all of these bolts are "wiping" the lube off and they are wearing out.

Funny... I never have this problem.

 

[Ggmac]

Ah case harmonics ! All these years of chambering , threading , and bench shooting just went up in smoke . This is the Internet .
Just do what cat shooter suggested . Done , easy peasy.

 

[bigedp51]

Since almost ALL match rifles are set up so the bolt handle will drop halfway down on a case (which means that there is zero clearance), then you are saying that all of these are "wiping" the lube off and they are wearing out.

Funny... I never have this problem.

CatShooter, I'm guessing you never watched the Star Wars movies and heard a female Ewok scream.........

My M1 and other rifles never scream in pain.

If it slides - Grease it. If it rotates - Oil it.

http://www.garandgear.com/m1-garand-grease

 

[CatShooter]

Since almost ALL match rifles are set up so the bolt handle will drop halfway down on a case (which means that there is zero clearance), then you are saying that all of these are "wiping" the lube off and they are wearing out.

Funny... I never have this problem.

CatShooter, I'm guessing you never heard a female Ewok scream.........

My M1 and other rifles never scream in pain.

If it slides - Grease it. If it rotates - Oil it.

http://www.garandgear.com/m1-garand-grease

Ed.. you're so badd. I should report you to the admin. ;D ;D ;D ;D ;D ;D

If I had seen that picture years ago, my Ex might not be my Ex.

 

[savagedasher]

BigEd has posted, w/pics, the simplest, easiest method of checking how much clearance remains between the base of fired brass and the bolt face that I’ve seen:

Partially seat a spent primer so leaving it standing proud, stick it in the chamber and gently close the bolt.

The bolt face shoves on the spent primer so pushing the case forward until the case shoulder butts against the chamber’s shoulder, and then it’ll seat the spent primer deeper though still leaving it standing proud by an amount equal to the clearance that’s left between the bolt face and the base of the fired case.

Measure the amount the spent primer is left standing proud and add that to the case base to shoulder datum dimension, and that’ll be plenty close enough to the bolt face to chamber shoulder datum dimension.

, Thanks Why didn't I think of it. :'( :'( :'( Larry

 

[speedgun]

As I stated previously, Thank You for taking the time to provide input to my question. A lot of this discussion is past my current state of expertise but I'll get there. I understand the concept of backing the die out, and that is what I plan to do, it just seems incredible that RCBS says to touch the case and then screw the die in 1/8 to 1/4 turn, and that may be what's causing a condition which is very dangerous.
I reload several calibers and after looking at some my other reloads for different calibers, it seems that this case ring issue is much more prevalent in the 25-06 rifle than the others. I'm beginning to wonder if I have a chamber issue.
I plan to purchase one of the Hornady gauges, but I've seen a tool that you chamber into your rifle and it is supposed to give you a go/no go measurement. Is it possible that I have problem with my chamber that would cause an issue with a properly sized case.
Thanks....Larry

 

[CatShooter]

As I stated previously, Thank You for taking the time to provide input to my question. A lot of this discussion is past my current state of expertise but I'll get there. I understand the concept of backing the die out, and that is what I plan to do, it just seems incredible that RCBS says to touch the case and then screw the die in 1/8 to 1/4 turn, and that may be what's causing a condition which is very dangerous.
I reload several calibers and after looking at some my other reloads for different calibers, it seems that this case ring issue is much more prevalent in the 25-06 rifle than the others. I'm beginning to wonder if I have a chamber issue.
I plan to purchase one of the Hornady gauges, but I've seen a tool that you chamber into your rifle and it is supposed to give you a go/no go measurement. Is it possible that I have problem with my chamber that would cause an issue with a properly sized case.
Thanks....Larry

"... it just seems incredible that RCBS says to touch the case and then screw the die in 1/8 to 1/4 turn, and that may be what's causing a condition which is very dangerous. "

Well, Speed... keep this in mind.

When someone like RCBS writes instructions for a die, they have a lot of tools and presses to cover. There are lot of fragile presses out there that have as much flex as a soggy hot-dog roll.
Also, what no one likes to admit is, many of our reloading tools are not as precise as we would like to believe - so recommending what they do, removes a lot of slop in presses and chambers - kinda like making it "one size fits all".

And... many reloaders do not have the technical acumen to grasp the intricacies of case management. There are reloaders that get 40 to 100 reloads from their cases, and reloaders that get 5 ().... and even here, many just "don't get it"... so when RCBS writes simple instructions, they are just that - the simple version.

Also, for the general shooting public, most folks use neck sizing dies which eliminate this problem entirely - but neck size dies are not kosher on this websire... so you will get recommendations to get $150 worth of guages and tools to fool with, instead of getting a neck size die... it is the price of being here among the elite