No. 1 should have been loaded prior to 1923, going by the primer style.
No. 2 is a more "generic" headstamp, but was likely loaded for commercial (civilian) sales.
No. 3 is Australian. and the "2Z" shows that this was loaded with one of the early forms of flake nitrocellulose powder, instead of cordite.
No. 4 is almost certainly marked as "G.F.L", loaded by Fiocchi.
Gun control in Canada: making the streets safer for rapists, muggers, and other violent criminals since 1936.