The ResultsThe failure mode was the same for every case in the test: the case mouths split (see Figure 3). This makes sense. The .38 Special is a straight-walled, low pressure revolver round. The primer pockets won't loosen up, there's no case stretch, and the chambers are fairly tight. That leaves "cracks due to work hardening" as the most likely failure mode, which is exactly what happened to these cases. During loading, the case mouth is first flared, and then roll-crimped, and then forcibly flattened during firing. It is no surprise that the mouths split because the mouth ends up getting worked much more than any other part of the case.
split second velocity reloaded crack
Download File: https://tinurli.com/2vAqbt
The splits start out tiny - less than 1/16th of an inch long. You can barely see them, but they're easy to feel if you run your fingernail around the case mouth (see figure 4 to see one of the tiny splits). The first couple of times I detected these tiny splits, I tried loading the case one more time. Although the rounds with the tiny splits fired and performed normally, the extracted cases showed significant (about 3/8" long) cracks like the one in Figure 2. After seeing what happened when I loaded cases that were starting to split, I decided to "retire" the remaining cases at the first sign of splitting. 2ff7e9595c
Comments