I will elaborate on my short post.
The term "most secure method" has come up in relation to the mailing of firearms previously. Priority is considered more secure than Xpress or Expedited with signature by CP, apparently becuse the parcel is in their hands for a shorter period of time. Less opportunity for it to go astray. There has been no other report that CPC will require PAL information, or evidence of legallity before accepting a parcel containing a firearm prior to accepting it for delivery. It is CP practice to post information about restricted items and require a declaration that a packet does not contain unacceptable goods. The CP website suggests that information about mailing firearms be obtained from CFC, 1-800-731-4000.
As far as I know, the CFC does not mandate the use of Priority. My next stop is to check the CFC website to see if there are new regulations posted there. If I can find anything there, I will report it. Edit. I could find nothing new at the CFC website.
There is a section on the CP website listing changes effective Jan. 15th. There is no mention of Priority being required for mailing firearms. The prohibition on mailing inert ordnance which was discussed earlier at CGN is there, and this prohibition was well publized. Most of the Jan. 15 changes relate to rates.
Concrete information - a formal policy statement, a posted copy of any regulations, links to a site, specific details, etc. would be useful. It is important to know exactly what the requirements are.
Some time ago, the x-raying of personal checked luggage at airports became routine. If there is a concern about attacks on aircraft, then it is only reasonable to expect that all goods travelling by air be x-rayed. This would include airfreight and mail travelling by air. If there are new additional requirements for mailing firearms, failure to comply with them - mailing "sporting goods" or a "tubular pressure containment device" would be a bad idea.