Measure the base of the case just above the rim, now measure just above where the carbide ring stopped. If the upper measurement is smaller than the base diameter you are over sizing the brass when using carbide pistol dies. In the photos I can "SEE" the case was over resized and the case is smaller in diameter where the carbide ring stopped.
Using a pistol case gauge helps when making die adjustments, the gauge diameter is minimum SAAMI chamber diameter. A carbide die should be adjusted so the case fully enters the case gauge without binding. Any more downward adjustment will over work the brass, and if you notice the case cracked and failed just above where the carbide ring stopped. The brass was over compressed and caused a hairline fracture where the brass is the hardest in the base. Meaning the brass cracked from being squeezed too much.
Below, from the Sierra reloading manual, Hornady and Redding.
(for slicknova and ted_dent to read and grasp) "When all else fails read the manual".
Carbide Sizers
Carbide sizing dies have become tremendously popular in the past ten to fifteen years, and for good reason. As we have already seen, carbide dies do away with the necessity of lubricating cases prior to the resizing process. They do require some attention to how they are set up, to avoid damage to the die, and obtain best results. The often repeated advice to screw the die body down until it contacts the shell holder, will give poor results with a carbide die and may even result in cracking the carbide insert. NEVER adjust the die body down so far that it will contact the shell holder. Carbide dies for straight-wall cases are not designed to full-length resize, and are frequently adjusted to give what amounts to excessive resizing. This often results in an undesirable bulge slightly above the extractor groove. Often called the “Coke bottle” effect, this will cause the brass to be worked excessively and can lead to reduced case life. The only portion of the case that needs to be resized is the area that is expanded by firing. For use in revolvers especially, the case need only be sized enough to allow the case to chamber freely again. Often, this may involve sizing only half the length of the case body and is in effect, neck sizing. If this is enough to allow the case to be chambered easily, then the die is adjusted down far enough.
This will avoid overworking the brass, and will eliminate the so-called Coke-bottle effect.
Hornady Die FAQ
Question: My Titanium Carbide Resizing Die is leaving a ring on the bottom of my case, is there something wrong with my Die?
Answer: The size of the carbide ring inside a Titanium Carbide Sizing Die must be small enough to allow the case to accept a bullet with adequate neck tension. Thus, the bottom of a case may be sized a little more than it has to be. Usually, backing the Die away from the Shellholder to size approximately ½ of the case or enough of the case to hold the bullet will rectify the problem.
Dual Ring Carbide Sizing Dies
Redding has solved the problem that has plagued ordinary carbide dies since their invention. The little ring in a standard carbide die had to do double duty. It sized the top of the case to properly hold the bullet but then continued to size the whole body of the case as well. Unfortunately, these two areas need to be sized at different diameters, so carbide dies of the past have always been a compromise.
Redding's solution to this problem is a unique (patent pending) design, incorporating two carbide rings within one sizing die. The upper ring is positioned to size only the bullet retention portion of the case while the other is located to properly size the case body without overworking the brass. Sized cases will not only look and function better but brass life will increase.
TC
