Sleeved barrels from the maker can cost more. Back in 2016 when I asked Purdey they quoted 19,500 pounds, which did not include shipping, customs etc.
WOW! Purdey wanted 19,500 BPS for SLEEVED barrels? Sounds more like NEW barrels and Purdey is always more expensive that almost any other maker.
I inquired extensively about an additional set of 20 gauge chopper lump barrels for my lightweight Harkom 16 earlier this year and was quoted numbers as posted in my first post. Of course, if you buy from any but the maker, the rib will not bear the maker's name and address.