Ian, you're worrying too much, these things are over engineered and the only thing that will distort that receiver is a club hammer which I know feels like an option with the FTP, but trust me stick with it and you'll finally get it performing.
Vinny, we must be cut form the same cloth as the first thing I did after bolting the action back in was also to run a tenner right along the action to check for fit...
Fundamentally the FTP is an accurate, comfortable, good looking rifle, it just needs tweaking a bit to get the best from it but once there it's easily as good as an German offering except in the trigger department.
That's not to say that the trigger is rubbish, far from it, it's just that Anschutz/FWB make the best triggers bar none in my humble opinion. The FTP trigger (once set up) just requires more care to get the best from the rifle.