Home Forums Hunting & Shooting Ask The Gunwriters Blown primer

There is a thread here with a list of the Winchester Primer lot numbers of the defective primers.

Found it.


Winchester Primers

Have you checked your firing pin/spring? I struggled with similiar symptoms, changing primers and checking for any additional pressure signs. These were established loads with H4831 with no history of excess pressure. Some blown/pierced primers finally convinced me to have my old Pre-64 examined; it needed a new firing spring.

The issue a number of us have had with Winchester primers is their splitting down the side and/or a pinhole leak at the outer edge. This should be unrelated to firing pin symptoms.

Five hot reloads can expand heads and primer pockets especially with soft brass. It also sounds like you started with the max load which is not a good idea. Could be bad primers, head space, oily bore or case, bolt setback or any number of things in addition to bad primers. R26 is unusual in not showing any traditional pressure signs until you are really high up there. I suspect it is so progressive the maximum pressures are further down the bore and affect the case less than single base or non progressive powders but this is just a guess on my part.