tank1949 I have a SA M1A that I spent a fortune on 4 different mounts and loads trying to get one to work and not have the rifle stove pipe brass. New ejector button spring too!!!! I read a lot of article from different forums.
SADLAK responded to my concerns that it was due to not having proper grease in needed points of stress within my action to assist in cycling.
The M14/M1A is a design that runs on grease, not gun oil. Use of any lube other than grease can cause all sorts of problems.
Tony Ben has made a few instructional videos that you can search for, he also created an excellent pdf, here is the link.