hello,,i thought i answered this already but i guess i jumped the buttons ,,

,,your hellis shotgun is british origin,,the firm is once again making shotguns and you may be able to get some info from them ,,mabey try a search online ,,i can tell you this much ,,most hellis shotguns in the us are 2"12 bores and values for a boxlock may surprise you ,,for a non ejector model book values state 1000-3000,,and if yours is a ejector model prices are stated as 1500-50,000 and i didn't put an extra 0 in ther either ,,you need to find someone who knows british doubles to get them properly appraised for insurance values and i'd look online to see if you can find any contact info for the firm ,,there on the west side of london from what my 2009 standard catalog of firearms is telling me ,,hope you have the ejector model,,

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bigcurt