I see and I noticed that when I bent mine... What I did was snug things up and then use your fingers to line things up as best as possible. The flat does not get bent over this so when I bent my flats the receivers came out fine and the finished gun works great...
we are now enlarging the front trunnion pin hole and centering the flat better... I am very happy with the results...this method takes a little longer per flat but it works .... we have 6 flats bent and have 11 more to go.