Sir;
I have never found any indication that Boswell's had any grading system for their guns. Your gun is a Birmingham made gun and it was probably made for pigeon or wildfowl shooting. It is in very good condition and from the engraving style it would appear to have been made in the mid 1930's. Game scene with bold English scroll was a mainstay engraving style of the Birmingham trade during that time frame.
It is typical of the mid-level quality Birmingham guns, but not a top tier quality boxlock as it does not have the four features within the action that one expects from a top quality boxlock gun: a Scott spindle (has a Greener style top lever works), scroll back, intercepting sears, and I doubt that it has a rocker safety--you can determine if it has the rocker safety if you examine the trigger plate to see if there is a small 1/4 inch long slot behind the triggers.
From my experience the majority of Boswell guns were Birmingham made, although some of their London pattern SLE's appear to have been made in London.
I believe that Chris Batha is now living in America and he has the Boswell records.
Best Regards;
Bv
Last edited by bushveld; 11/18/11 08:17 PM.