Originally Posted by
akajun
More like a Mill Job, this is a falling block, not a bolt gun. You may be able to fixture it but I wouldn't count on it easily.
The fact that it takes three firings is strange, if it was a firing pin/primer flow issue I would think it would be a problem from the first firing. Take a pick of the bolt face both with and without the firing pin protruding. Also so pics of fired brass, first firing and third firing. If its a bolt face issue Id expect to see smearing on the brass and primer.
If it is a primer hole issue, have you tried magnum or military primers? they have a thicker cup.