Well, I measure a new Wichester primer pocket and it came in at 5.25 mm which is good and right on with yours. I went back to try to remeasure the Igman pocket and I couldn't get a consistant reading largely due to the primer still being inside. The first one that I took a measurement off of I drilled out the primer and pocket to see how the new primer would fit and it squezzed in real nice, but when I tried to use my hand installer or the press installer on the original pocket, there was no way those primers were going in. So, my first real issue is the real small primer flash hole! How do you punch your primers out? I tried several dies pins and none would fit the Igman brass ???? I think I am going to sacrifice one decapper pin and grind it down to fit and then retake a measurement on the pocket. This is so dumb??