Well, I own both a Non-Registered Magnum and a 27-2. I have shot both. The pre-war long action of the RM's and NRM's are a true delight to shoot. There was some tribal knowledge lost between the RM days and the 27-2 era, and I don't think that we will ever see the attention to detail and fine manufacturing qualities of the pre-war guns again.
PS- Quinn - you are welcome to shoot my 27-2 for comparison against your FBI Reg Mag.....but ya gotta let me shoot the FBI gun
Here is the Non-Registered Magnum after the first range session.
And here is the pair together. The 27-2 is wearing genuine Fuzzy Farrant stocks as they really fit my hands well. The NRM gets some period correct sambar stags with a Tyler adapter when the mood strikes me.