My 80 year old neighbour uses a pair of Wm. Evans boxlocks in 12 bore. He had them sleeved about 20 years ago, and also chose 28" barrels rather than the original unfashionable 30" barrels. He also specified 2.75" chambers. They work a treat and he shows up all the lads with their funny over-under thingies.

So he is now set up perfectly for the next 20 years, even if the mooted ban on lead shot does get imposed here in the UK...

HB