I have been shooting the Sig for about a year now and this has just started happening. I thought it might be my grip also, but when I tested the loads, I made sure I wasnt contacting the slide lock and it still didnt lock back on the load with 4.2 gr.
The pistol was purchased in 1984 and was shot very little until I started to compete in the local IDPA matches about a year ago. I am using the Mecgar mags, so I don't think it is the mag spring or follower since it has happened with more than one mag. Is there any internal springs which could be the problem?
Thanks