What caused this?

[desertrat1979]

Ok, I may already know the answer to this. But a little help from the experts.

I noticed this after a trip to the range. I havent been reloading for too long, so this is a first for me. The brass is winchester, 30-06. I have about a dozen loads on this, so I suspect this is the end of its life as far as the brass. But, I have some newer winchester brass showing some faint ridges in the same area. The rest of my brass, Remington, PMC, and Federal, show no signs. I have changed nothing on the rifle, nor the way I reload. I am using a Lymann press and dies. Most of the loads were 178 amaxs with RL-22.

 

[desertHK]

Re: What caused this?

As you know, that's complete case head separation from wear and tear of the aging brass. Depending on how hot one loads their ammos, 10x with win brass is not bad at all. Most important point is to make sure that you catch and discard those old brass before loading them again, because severe injuries can occur. That's also the reason why I tumble my brass every time before resizing them. It is so that I can inspect the brass and discard any questionable ones. Stay safe.

 

[Halfnutz]

Re: What caused this?

Straiten out a paper clip and put a very small bend on the end of it. insert it in a case and drag the hook along the side, this will allow you to feel the thinning of the case above the web. Discard them before the head seperates.

 

[Jonathan]

Re: What caused this?

Supposedly you can minimize head separation by having a highly polished chamber (low friction), but the tradeoff is higher pressure on the bolt.

 

[Victor N TN]

Re: What caused this?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jonathan</div><div class="ubbcode-body">Supposedly you can minimize head separation by having a highly polished chamber (low friction), but the tradeoff is higher pressure on the bolt. </div></div>

Personally I wouldn't do that. I know a man that got a bolt in the face. He lost a lot of cheek bone and most of the sight in his right eye. Good thing it wasn't a high case volume load.

But you do what you think is best.

 

[padronanniversary]

Re: What caused this?

ouch, that just sounds painful, a bolt in your face. How does polishing a chamber cause this ?

 

[Rob01]

Re: What caused this?

Can happen from over sizing the brass also. When FL sizing you only want to bump the shoulder back about .001" so you are not compressing and the brass and then having it stretch out more than it needs to in the chamber. An RCBS Precision Mic will let you get those measurements.

 

[nolo263]

Re: What caused this?

Case was work hardened and cracked..

 

[The Mechanic]

Re: What caused this?

Undercharging can cause this also.

 

[Fuzzball]

Re: What caused this?

Robo1 has the answer. Far too many people simply "follow instructions" blindly and jam a fired case into a FL sizer as far as it will go. That almost always guarentees the case will be sloppy fit, head to shoulder, in the chamber. Fire it and the forward portion of the case will firmly seize against the chamber walls and the pressure will force the case head back until stopped by the bolt face. Repeating this too often results in head seperation, photos above.

FL size so the shoulder is barely bumped back and the number of times they can be reloaded, safely, becomes a question of how long it will be before (safe) neck splits occur.

But, yeah, discard any brass left in that one's batch, for sure! It is surprising that you had no serious cousequences of that head seperation.

 

[Grump]

Re: What caused this?

Before anyone else asks again(the errant thread-reader deleted his post...),
From the OP:

"The brass is winchester, 30-06. I have about a dozen loads on this, . . ."

Back to the question--that's a normal end-of-life casehead separation. Technically, it's head clearance, the gap between your sized case all the way forward in your chamber, and where the boltface lies.

I got only 2-3 reloads out of one batch of brass from way over-sizing it compared to my long chamber. So, I backed out my sizing die and am getting at least twice that many loads (semi-auto that's rough on brass)...then I re-barreled and the loaded rounds didn't fit my new chamber!

Turns out that was not a headspace difference, by my 20-year old die was either too fat just behind the shoulder area, or had just worn too much. A body die fixed that.

Anyway, you might be able to back your sizing die out either 1/8 or 1/4 turn, still be able to chamber your reloads, and get a few more reloads out of your cases.

I really don't like the paper clip inspection method. The stiff stainless steel spines out of old windshield wiper blades work a lot better, can be cut to a more handy size than tiny paperclips, don't roll around in your fingers, and have a nice spring stiffness to them. I also recommend that the end of the little bend be slightly sharpened to give a more sensitive reading.

My cases will show a dip and still be good for 1-2 more loadings. When the dip catches the sharpened tip, or the outside of the case shows a tiny bright ring, they go in the scrap pile for recyling.

 

[okiefired]

Re: What caused this?

I'd say that case was spent bout 2 or 3 loads ago. I'd sure closely inspect what you have left in that batch (or just toss them) and keep a closer eye on them from now on. Thanks for posting, makes me remember to keep a close eye on mine. 12's an awful lot of load for Win brass from what I hear.

okie

 

[amc]

Re: What caused this?

You may want to include a neck die into your die set, so that you are not always working all the brass. But 12 is quite alot.

 

[TOP PREDATOR]

Re: What caused this?

i use a bobie (hair) pin clipped in the middle of the bend so there is a bend in it. flexible / soft enough to feel the crack that forms INSIDE the case. for safety sake i also only reload brass 4 times on target, then save the fifth and final reload for hunting. so far i haven't had a problem restricting myself to the 5 reloads per case.

 

[sobrbiker883]

Re: What caused this?

For the paper clip test, is the impending defect a well defined depression?
I feel a gentle dip at the base of some of my 308 cases, both 5-6X reloaded LC Match, and 1-2X fired Lapua??

 

[TOP PREDATOR]

Re: What caused this?

while lightly scraping the <span style="text-decoration: underline"> </span> inside <span style="text-decoration: underline"> </span> of the casing towards the bottom and rotating it at the same time, you should feel a "tug" or "stopage" or "resistace" on the paperclip or bobbie pin.

that is where the crack or seperation is grabbing the clip or pin as it leaves the smooth wall of the the casing and dips inside the crack. kinda like running your finger over a table that has a removable leaf in it and the expansion joint runs down the center.

remember the seperation starts on the inside, you can't see it.

if it's on the dip is on the outside, it can be many things from head space, to your chamber, to your sizing die.

the picture looks like case head seperation though.

 

[sobrbiker883]

Re: What caused this?

Thanks, what I'm feeling is just kind of a gentle dip on the inside- its present on the 1X fired Lapua, and just feels rougher (dirtier) on the LC. Neither feel like the "table leaf" analogy.

 

[Rafael]

Re: What caused this?

If you are finding that on 1x Lapua it's likely you have a very long chamber(bolt-face to shoulder).

My theory?
You might get more from that brass if you do the first firing with the bullets jammed. This may help keep the head against the bolt allowing the shoulder to blow out rather than the case siezing against the chamber walls before it can move back...resulting in the stretch at the web.
Of course, minimal shoulder bump on all future sizing will help curb it as well.

I get a shitload of life out of my Lapua cases, to the point it costs me less than standard primers....per shot.

 

[desertHK]

Re: What caused this?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rafael</div><div class="ubbcode-body">If you are finding that on 1x Lapua it's likely you have a very long chamber(bolt-face to shoulder).

My theory?
You might get more from that brass if you do the first firing with the bullets jammed. This may help keep the head against the bolt allowing the shoulder to blow out rather than the case siezing against the chamber walls before it can move back...resulting in the stretch at the web.
Of course, minimal shoulder bump on all future sizing will help curb it as well.

<span style="text-decoration: underline"><span style="font-weight: bold">I get a shitload of life out of my Lapua cases</span></span>, to the point it costs me less than standard primers....per shot. </div></div>

1+. I stop counting the number of times I have reloaded the curent batch of Lapua brass. Still very compulsive about checking for signs of separation. Can always buy more brass, but not your face.

 

[Greg Langelius *]

Re: What caused this?

A properly sized case will cause a slight dragging sensation as the bolt is closed, which is not felt on an empty chamber. This ensures that headspace is kept to a working minimum, which can decrease case stretch. This case stretching is the root cause, combined with case resizing, that drives the case head separation process.

The feeler method, combined with case resizer adjustment that produces the mild drag condition I suggested, will postpone case head separation, and also identify those case which have aged themselves out of the reloading rotatation.

Greg

 

[858]

Re: What caused this?

Getting ten loads from brass is dang good, I'd proudly retire it.

 

[desertrat1979]

Re: What caused this?

Well I proudly retired most of my brass. The only exceptions are some of the newer federal and winchester rounds. Time to look into some new brass.

 

[308sako]

Re: What caused this?

.

 

[Victor N TN]

Re: What caused this?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: PadronAniversary</div><div class="ubbcode-body">ouch, that just sounds painful, a bolt in your face. How does polishing a chamber cause this ? </div></div>

When the bullet starts moving and the brass starts expanding, there has to be SOME friction between the brass and the chamber. This give the brass something to hang on to. If the chamber is too slick or maybe some case lube left on the brass, there isn't enough friction to hold the brass in the chamber. This causes the shot to put way too much of the firing pressure onto the bolt. Most bolts are not made to have a lubed case fired in the chamber. They just won't hold under that kind of pressure.

That being said. I don't want my chambers to look like they have been ground by 80 grit either. But there is a big difference between being smooth and being slick.

Most bolt lugs are just not made to handle that kind of pressures. With a pierced primer a lot of the gasses go out through a vent hole in most receivers. They are usually located near the front of the bolt face either on the right or sometimes the left of the receiver. Some will go back into the bolt and grime up the works there around the firing pin. And some will go into the trigger itself. You need to have tools somewhere to take care of the cleaning.

I hope I helped explain it and didn't muddy it up more for you.