I took the gun out and fired a few rounds of Winchester white box 115 through . It would lock open at times on the mag hold open even when there were rounds in the mag . It did this with the original mag and with a new mec gar mag.
I was always able to get it to feed a new round by pulling the toggle back a little . I inspected the hold open spring and it not broken and appears fine .
I added a pic of the front of the frame with the script letter also.

Kirk