Case Diagnostics — How to Find Defects in Cartridge Brass

Ever wondered what caused a particular bulge or marking on a case? And more importantly, does the issue make the case unsafe for further use? Sierra Bullets Ballistic Technician Duane Siercks offers some insight into various issues and their causes in two Case Diagnostic articles from the Sierra Blog.

Incipient Case-Head Separation
This is a Winchester .308 Win case that has a real issue. This case has a very obvious incipient case head separation in the process of becoming a complete failure.

This is most commonly caused by over-sizing the case causing there to be excess headspace on the case. After a few firings and subsequent re-sizing, this case is just about ready to come completely apart. Proper die adjustment is certainly a requirement here. Of course this case is not safe to reuse.

Excessive Pressure (Load Too Hot)
If you will notice in the picture of the case rim, there are two pressure signs to notice. First, look at the primer. It is basically flattened to about the max of what could be considered safe. If this was the only pressure sign noted, I would probably be fine with this load, but would constantly keep an eye on it especially if I was going to use this load in warmer temperatures. This load could easily cross into the “excess pressure” realm very quickly.

There is another sign of pressure that we cannot ignore. If you’ll notice, there is an ejector mark apparent that is located over the “R” of the R-P headstamp. This absolutely tells us that this load would not have been in the safe pressure range. If there were any of these rounds loaded, they should not be fired and should be dis-assembled. This case should not be reloaded.

Split Case-Neck
Here we have an R-P .22-250 case that has died the death. Everything looks fine with this case except the neck is split. This case must be tossed.

A split neck is a normal occurrence that you must watch for. It is caused by work-hardening of the brass. Brass cases get harder with age and use. Brand new cases that are stored for a period of time can become hard enough that they will split like this case within one to two firings. I have had new factory loads do the same thing. Then as we resize and fire these cases repeatedly, they tend to get harder and harder. Eventually they will split. The life of the case can be extended by careful annealing practices. This is an issue that would need to be addressed in an article by itself. Of course this case is no longer usable.

In the classes that I teach, I try to use examples like this to let the students see what they should be looking for. As always, if we can assist you, whether you are new to reloading or very experienced, contact us here at Sierra Bullets by phone at 1-800-223-8799 or by email at sierra@sierrabullets.com.

Dented Case Body
Here we have a Lake City 7.62×51 (.308 Win.) case with two heavy marks/dents in the case body.

This one may be a bit of a mystery. It appears as if this case may have been caught in the action of a semi-auto rifle when the firearm jammed or the case failed to clear during the cycling process. I probably would not reload this case just to prevent any feeding problems. This also appeared to be a factory loaded round and I don’t really see any pressure issues or damage to the case.

Multiple Problems — Lake City 5.56×45 unknown year.

This case has suffered multiple failures and cannot be re-used. First its has have a very rounded shoulder that is split. Upon first look it was obvious that this round had been a victim of excess pressure. The firearm (perhaps an AR?) was apparently not in full battery, or there was possibly a headspace issue also. While taking a closer look, the primer was very flat and the outside radius of the primer cup had been lost. High pressure! Then I also noticed that there was an ejector mark on the case rim. This is most certainly an incident of excessive pressure. This case is ruined and should be discarded.

CLICK HERE for MORE .223 Rem Case Examples in Sierra Blog

To see more examples, view both Part I and Part II of the Case Diagnostics from Sierra Bullets:

» Reloading 101: Case Diagnostics Part I
» Reloading 101: Case Diagnostics Part II

It is very important to observe and inspect your cases before each reloading. After awhile it becomes second nature to notice the little things. Never get complacent as you become more familiar with the reloading process. If ever in doubt, call Sierra’s Techs at 1-800-223-8799.