With all the reports on here about light primer strikes, you're first questioning the 450s (that you use successfully in another rifle) or the seating depth (the same you normally do on your other rifle)?
I applaud you for giving it the benefit of the doubt and not jumping to conclusions, but come on!
I just went through the Nucleus Light Primer Strikes thread, and I guess I've got a little homework ahead of me to attempt a troubleshoot before heading back out to the range (ie. at minimum, bolt disassemble and degrease).
Action serial number is 588, trigger is a Timney 510.
Not whining - yet - just info in case others have similar experiences. Will follow up...