After the WWI,Canada had thought to build the P-14 at the Ross factory,but England choose to stick with the SMLE.they had a lot of them. Since the rifles were to be used at home ,30.06 makes good sense,our neighbour to the south used that caliber as well.The brilliant C.D. Howe made sure we had ammo for them as well.The Enfield 30.06,the correct Canadian name, works better with rimless cartridge than the P-14 with the rimmed 303,too. I have one of the bought,not lend-lease, rifles sporterized.