Find a Class III dealer in your new state and check with him. You will need a BATF packet that will include two fingerprint cards and a Form 4 card I think. Take the fingerprint cards to your local PD and have them fingerprint you. You will need two Passport style photos of yourself as well. You will send the photos, fingerprint cards, Form 4 and a check for 200$ to the BATF and wait 90 days to a year for them to send you the Form 4 with the approval stamp. Then you can buy the sear (which may cost you 3500$+/- depending) and install it. You should, after getting the Form 4 back from the BATF, make a copy to be kept with the rifle and keep the original in a safe deposit box or in your gun safe if it's fire proof.
Again, check with a Class III dealer in your new state because I may have missed something. Good luck and enjoy.
Guns cause crime like spoons cause Rosie O'Donnell to be fat!
I hunt, therefore I am.