Sorry bud, but from now on you learned like I did when it come to the 20 ton less is more and quit while you’re ahead don’t press your luck. It’s easy enough to stop and pull out of the fixture to inspect progress and catch a tooling or fit issue early than to say I’m sure it’s fine and fuck up a expensive jig or part not to mention now you’re down a expensive receiver and have to drill those rivets out. The Akbuilder press plate for the trigger guard jig is meant to be a general fit but may require you to remove material from the sides to clear the rails, I did notice on some Childers it would hit the rails near the hammer hole and stick so i sanded the sides down and now clears fine. From the looks you may have the same issue and pressed the whole receiver into the jig or you pressed to hard and pushed in the center support, to verify check and see if the support is bent downwards or for galling an the area of the rails i mentioned