Powder Ignition Failure

[bob q]

Some powders will do this in military rifles . It is caused by several factors , the more of the factors you have , the more likely it is to happen . 1. A bullet too small for the bore , 2. an oversized chamber for the case being used [ or the case is too small ] , 3. too much neck clearance in the chamber , 4. cooler weather , 5. the powder used [ I-3031 is one of the worst ] , 6. too light of a charge . You probably have all of those listed . It is NOT the primer or crimp.