Personally, I don't think HK heavy barrel untreated steel MR556 14.5" and 10.4" would "sell them like hotcakes". If the barrels are made here in the US, then chrome lined 416 barrels would certainly sell well. But selling untreated heavy profiled barrels I don't think would be very popular. Just as with the 16" barrel, it would still need to reprofiled and Nitride treated. There just wouldn't be the step of shortening and rethreading that would not have to be done. There certainly be a market for MR556 14.5" and 10.4" barrels, but not anywhere near what chrome lined 416 14.5" and 10.4" barrels would be. YMMV.