Jim is correct. Your primers are not hot enough for the ball powder to be shattered and ignited by the primer blast. That is why the yellow lumps of unburnt powder. Ball powders are well known for needing the extra brisance of a magnum primer. The extruded powders do not need the magnum primer is standard rifle cartridge loadings but would be needed if the round is considered to be in the magnum category. If you have tried a good magnum primer and this still happens then you have other problems that you will have to address.
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