I am doing the whole insert front first and swing to back as in the manual. I am definitely getting the front latch, I can see that with the chamber open. The problem seems to be the magazine release latch is staying vertical after I have swung the back in, as in the magazine's catch is too thick to get past the magazine release latch or some clearance is wrong somewhere and the magazine release latch is just resting on the magazine's catch rather than securely below it. I doesn't seem to be an issue with the back not getting in far enough, as I can see that the top of the magazine's catch is