When you have ejection failures usually it is an EXTRACTOR problem. The extractor is not holding the case against the bolt face well enough for the ejector to get a good solid hit on the case.
A known problem is the pin that holds the extractor in the bolt. If it is a ROLL pin, made of thin sheet metal in a spiral shape, it can be a problem. Replace it with a SPLIT pin, made of thicker metal formed into a "C" shape. This solves many of the extractor problems. The pin is 1/8 X 3/4 and is of a common size.
The extractor design is much like a 1911. The hook needs to be properly shaped to hold the case against the bolt face. The tension must be strong enough as well. Any gunsmith famililar with tuning a 1911 can solve this.
