Start of case head separation? (It is a chamber scratch!)

[pdhntr]

I've used the paperclip test on multiple pieces of brass and don't feel anything out of the ordinary. I see the same tiny cut on both twice and three times fired brass.

Its Hornady 6.5 creedmoor.

I have been full length sizing and have not been bumping the shoulders back (just got the part and will be doing it going forward)

Is this the start of case head separation? A lot of my 2x and 3x fired brass have it.

Would you guys toss it? I have a lot of Hornady brass lying around

So it isn't case head separation.

Looks to me like a ding from a sharp edge of a loading port. Maybe the case coming into contact with the rear of the loading port on ejection.

Maybe when operating the bolt quickly? Don't know what type of action you are using so just an idea.

Jim

 

[CA_Shooter]

UPDATE: I just realized that I tried a new technique for case trimming with this set of brass and I think the scratch is from the case trimmer. The scratch is near the area where the case trimmer clamps down on the brass

I have a batch from Hornady made 6.5 cartridges that I had shot once, and then trimmed, resized.

I have the RCBS case prep center and I was getting different length trimmings that last time i was using it. So I tried a new way to do it after a decent amount were sized too short.

The new technique was allowing the trimmer to slam down on the brass which made sure to get the brass trimmed consistently.

I have about 20 rounds that were cut short. This was before slamming the RCBS. All but one do NOT have the cut mark.

Most cases trimmed to size, which means they were trimmed using the slamming method do have the cut mark.

So I am pretty sure the cut mark is from allowing the RCBS case prep center to slam down on the brass! When doing the slamming I thought it was just allowing the brass to just press hard against to trimmer but I guess the clamps on it must also be pressing hard at the same time.

I'll test this out with a new piece of brass and report back

 

[marchboom]

Whatever you decide, if you scrap that case scrap the entire lot that was bought together. I've been there and after having a separation I started checking my cases of the same lot and fired the same number of times very closely. Many of them were right on the edge of separating. Just retire the lot and start over. Much better to have piece of mind than to say a few bucks and wonder, "Is this one going to come apart?"

Use the retired cases for non-firing work (playing with dies, using as case trimmer gauges, die set-up gauges, setting up a case annealer, etc.)

 

[CA_Shooter]

UPDATE: I was able to resize some brass today.

Turns out the scratch is NOT from:

•resizing die
•resizing mandrel
•case trimmer (which i thought it was)

I'll be loading the brass in the next few days.

This narrows the scratch to:

•bullet seating die
•hand primer
•my rifle firing
•my rifle extracting

So I'll try the above out and pay close attention

 

[varget204]

UPDATE: I was able to resize some brass today.

Turns out the scratch is NOT from:

•resizing die
•resizing mandrel
•case trimmer (which i thought it was)

I'll be loading the brass in the next few days.

This narrows the scratch to:

•bullet seating die
•hand primer
•my rifle firing
•my rifle extracting

So I'll try the above out and pay close attention

You Can Always Tell the Start of case head separation, with a bent paper clip,you always feel the groove or crack,you may not see anything on outside of case,the Sep. is usually 1/2-5/8" above base

 

[jelenko]

You Can Always Tell the Start of case head separation, with a bent paper clip,you always feel the groove or crack,you may not see anything on outside of case,the Sep. is usually 1/2-5/8" above base

And, sometimes, the groove is very slight. At times, I run the tip of the paper clip over the inside farther up the case body to get a feel for what 'flat' means; then go back to the suspected groove. Just that it can be that slight.

 

[F Class John]

Here's another example of what it looks like on the inside.
This may help too.

 

[0.1 Aggregate]

Guys, the OP tried the paper clip over a week ago, and opening up the case showed no separation. Read the entire thread before you post.....

 

[CA_Shooter]

Thanks to everyone who has been helping out. I have yet to find out the cause but i can knock out certain things.

I have loaded some dummy rounds, and tried them with both magazines that I've been using. I also loaded some resized brass. None of them caused the mark...although there were other scratches on the cases and bullets but they seem to be random scratches in different places.

So it Turns out the scratch is NOT from:

•resizing die
•resizing mandrel
•case trimmer (which i thought it was)
•Bullet seating die
•rifle loading a round without a magazine
•rifle loading a round with a magazine
•rifle extracting new brass



This narrows the scratch to:

•decapper
•hand primer
•my rifle firing
•rifle extracting spent brass

It seems the above four things are all I have not tested thus far. Its impossible its the hand primer but I listed it anyway. As for the scratch coming from the rifle firing vs extracting I don't think I can differentiate the two but I listed them both.

Next step is making time to go to the range to see if I get new scratches. I'm going to mark the brass with sharpies to indicate where current scratches are to see if new ones appear (I did this with the dummy rounds)

 

[searcher]

A circle on the brass in that location has, in very instance I have seen one - was just that - a warning of thinning brass. If showing after only three or four firings, you are almost certainly pushing your shoulders back too far and is made worse when using a factory full-length sizing die. Anyway - the paperclip test is best done with a paperclip that has been sharpened. When your brass is getting close to a real problem - you will notice a pronounced and VERY noticeable "trough" that the paperwork will fall into when gently sliding it in and out of the area where the circle is. There is a photo above that Uncle Ed posted showing the RCBS Case Master. That black little arm on that is the best thing I have ever tried for case separation detection. I don't use the Case Master anymore - but I do use that little black arm top check cases. If you can buy one by itself from RCBS - would be worth whatever they charge. Good luck.

 

[JFrank]

I’ve had a few come apart.... no joy..

 

[CA_Shooter]

Is it possible for case head separation to:

•only show on the outside of the case at first?
•not be a complete ring outside the case and only in about 1/10 around the case at first?

 

[varget204]

A Tip on bent paper clip, Smack end w/ hammer, make a thin edge,use a file if needed to shape,then Bend, the Smallest grove will be felt

 

[varget204]

Is it possible for case head separation to:

•only show on the outside of the case at first?
•not be a complete ring outside the case and only in about 1/10 around the case at first?

NO, they split from the inside out

 

[JFrank]

I could feel the paper clip catch just a weeee bit on the inside

 

[Fotheringill]

Decapper (dedicated) and hand primer should NOT cause this.

Decapper does nothing to the case except have a pin go down the middle.
Hand primer only touches the base of the case as far as I have seen.

 

[CA_Shooter]

Decapper (dedicated) and hand primer should NOT cause this.

Decapper does nothing to the case except have a pin go down the middle.
Hand primer only touches the base of the case as far as I have seen.

Agree - I ended up listing things that don't even touch the area just to list the whole process.

Although this area of the brass does go inside the hand decapper

 

[CA_Shooter]

I went to the range today and fired some once fired brass that I loaded. The once fired brass each had 1 scratch on the brass in the same location as the original image.

After firing the rounds today and extracting the brass, they each had one additional scratch on the brass.

I have tested dummy rounds where I loaded the round and then extracted the round using a magazine, and that brass did not get a scratch.

I also was able to close the bolt on spent brass, and then extract it. This brass did not have a new scratch.

So the scratch clearly has something to do with the firing mechanism.

Any ideas here? If its not case head separation what could it be?

 

[MislMan]

Mark the reloaded rounds with an index mark and fire a couple more rounds. Use the index mark to figure out the orientation of the cartridge in the chamber. Then you’ll know where to look within the chamber and port area for anomalies.

 

[jelenko]

Mark the reloaded rounds with an index mark and fire a couple more rounds. Use the index mark to figure out the orientation of the cartridge in the chamber. Then you’ll know where to look within the chamber and port area for anomalies.

So simple, but I usually forget this.