As most followers who have older Pre-Republic Petes in their collection will be aware,the dating of them can either be a pleasant experience or a real pain in the head.
It is all part of the unique Peterson ownership experience! When in doubt, study my late, great, old friend Mike Leverette's marvellous reference work, The Peterson Pipe Project, “A Peterson Dating Guide; A Rule of Thumb.”
Unfortunately the Peterson historical records are not very good for the Pre Republic period. So Mike's great reference piece is invaluable to collectors.
I recently started to focus on doing some long overdue cataloguing on my older Pets's. One of these is a very good lightly smoked 1928 made in Ireland 356.System 3. Photo below.
The "Made in Ireland" block format evident on this pipe can be a headache in dating Peterson pipes, since this same stamp was used in the late Patent Era as well as the late 1940s. So for a guide we must take into consideration the style of lettering Peterson used on their pipes. From the start of the Patent Era until somewhere in the early 1930s, Peterson used the "Old Style" lettering that used a forked tail "P" in Peterson. Fortunately this one had a hallmark (n)on the silver collar dating it to 1928.