Sorry guys-wasn't paying attention. Here's the short version
Pattern Welded shotgun barrels can be classified into three general categories, all starting with strips of iron and steel, but with different manufacturing methodology:
Twist (thin ribbons of layered iron and steel which were
NOT twisted before being wrapped around the mandril and hammer forged)
Crolle Damascus in many patterns (determined by how the iron and steel were 'piled' or layered in the billet and the twisting of the rods)
Laminated Steel (a higher ratio of steel to iron mixed together and ‘puddled’ before being formed into rods.)
LOTS of variants of Twist, but in general anything marked "Twist" is probably Plain Twist or Skelp. Stub Twist was felt to be a superior product and would be so labeled.
Long version here:
http://docs.google.com/Doc?id=dfg2hmx7_40dxk2scc7
http://docs.google.com/Doc?id=dfg2hmx7_69dxb227c6
http://docs.google.com/Doc?id=dfg2hmx7_162c3zhvkfx
http://docs.google.com/Doc?id=dfg2hmx7_282jmgkqxdp