A related idea came up at the Vintage Cup event where we had on our stand a 12g hammergun which we had sleeved down to 16g - it was a very light action, possibly a 16g action, but originally barreled to 12g. A serious clay shot who likes VERY heavy barrels was interested in having a good quality 12g gun (albeit with scrap barrels) sleeved down to 16g but with all the wall thickness left on. This would have given him a very heavy 16g with the barrel length, chokes and chambers of his choice but yet a classic 'antique' gun at his end! The price would also have been extreamily competitive when compared with a bespoke gun made to his unusual specification.
