My Ruger SR1911 9mm Commander stopped locking back on the empty magazine midway through a shooting session yesterday. It took me about 1/2 hour toremember to look to see if the take-down pin was fully seated. Sure enough it was half way out which causes the loss of the lockback feature. As a lefty I sometimes push the pin out from the right side with my support hand thumb inadvertently. Well I pushed it back in and presto, good to go. Whew. I didn’t want to have to send it to Ruger.