dgeesaman
Gold $$ Contributor
I’m not the OP but I agree the primers need to be seated against the bottom of the primer pocket.Interesting. Are you saying a primer with poor ignition and fail to fire will might contaminate the powder? Why are there only a couple of small clumps, the rest is I still normal looking. Non of the powder burned? Are the lumps at the front or back of the case? Your seating to 0.0025" depth, this is a problem. I think that as a first simple step he needs to seat the primer to the bottom of the pocket and make sure the powder looks normal and then see if the problem goes away. If this doesn't solve the problem it becomes much more difficult. My guess is that there is nothing wrong with the rifle. Just loading bad ammo. Did he find clumped powder when pulling bullets on cartridges that were loaded but never in the rifle? I fired several brands of non magnum primers in the winter for deer hunting. They all went off. The only primers I didn't have go off in 50 years were ones I seated just below the case head surface. They failed in the Summer.
My Creedmoor experience was that the primer spark left some powder clumpy and the rest unburned. In my case the primers were not soft seated but I think it can all contribute here.