Case Head Spearation Confirmation

[arrowshooter]

I just wanted to confirm that what I am seeing here is case head separation. I did have one let loose yesterday which had me looking closer at the rest of the fired brass from the day. This started as new PPU 8mm Mauser brass and now on it's 5th firing. The first three firings were at the top of the loading data for H4895 and the last two were mid loads. The shoulder bump averages .003".

['ol shooter]

Sure looks like it. Verify it by taking a look inside the case with an Otoscope or feel for a depressed ring in the brass with a straightened out paper clip bent at a 90 degree angle at the tip. Time to make keychains out of that brass, looks like.

[arrowshooter]

Thanks 'ol shooter. I did do the paper clip trick (well baling wire) and cannot say that I could feel a hang up in that area, but there was definitely some extra drag for sure. I will "clip" check the rest. Time to open a new bag of brass.

[divingin]

That looks pretty low on the case to be separation. From the web, the brass tapers into the case wall over some distance (1/4" to 3/8" at a guess.) Separation usually happens where the web ends, and the case hits wall thickness. I don't know about your caliber, but on 308 it usually shows up about twice the distance from your extractor groove to line measurement (roughly.)

That line is also awfully well defined. The stretched area I usually see is more of a band than a line, lighter in color and slightly matte compared to the rest of the case surface.

[arrowshooter]

Now I wish I would have been able to save the blown out case, but someone picking up brass showed it to me then he politely tossed it out into the weeds. It happened exactly where those lines are, about a third the circumference of the case. I am going to cut into one of these and take a look. I put up a photo of what I find. I am going to guess that the web on the PPU brass is shorter since I can get more powder in the PPU vs Federal.

[arrowshooter]

Case cutaway. Arrows mark the "line" and the corresponding thinning of the case in that area.

[JackEllis]

I have the pieces of a .308 case sitting on my desk that separated in about the same place. Something I picked up.

I wonder if we could get a sticky for this forum for photos of cases that have either separated or show the same signs of being about to separate that your photos show?

['ol shooter]

Yup, that's a separation in progress all right.

[arrowshooter]

Should I just go 4 and out on this PPU brass, or should I lessen the bump for the particular rifle that shot these? I did feel the stretch mark with the wire on cases without the line.

[colt11]

I would not recommend re-using brass that has a known defect, it's just not worth the risk.

[arrowshooter]

I would not recommend re-using brass that has a known defect, it's just not worth the risk.

Roger that.

[silvertriple]

Yup, that's a separation in progress all right.

Seconded.

You may even want to check headspace. Case head separation is an indicator of excessive chamber headspacing.

[Catch]

Thanks for the pics. +1

['ol shooter]

Seconded.

You may even want to check headspace. Case head separation is an indicator of excessive chamber headspacing.

Ditto. An easy way to check without a gage is to remove the firing pin and take an unfired round, put a piece of masking tape on the base of the case and see how many pieces it takes to prevent the bolt from fully locking. That will give you a rough idea. If it takes more than two pieces to prevent lockup, you are looking at gunsmithing or wall hanging.

[LynnJr]

Casehead separation is an indicator that you are over sizing your brass.