I've never had much to do with shotties (where I grew up duckshooting/clays just weren't popular) so I am on a "late in life learning curve". (OK I'm a confirmed gun nut so likely certifiable nuts).
I'm sort of swinging between .410, 28 and 20 gauge (besides the pigeons I have in mind a grandson who I hope to get shooting in a few years) but something I read has sort of distracted me from the pump/semi thing . . .
A shotgun writer of some note (well he made out like he was important anyway - a Pom of the driven shoot class of folk) pointed out that with a double barrel you have an instant choice of chokes, and that in a sub gauge this was a significant advantage as it extended your range quite a bit over a single barrel with only one choice of choke (at the time of firing). That makes quite a bit of sense to me, the likes of the Miroku mentioned by @GDMP is interesting . . .
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