Mandrel butting involves cold drawing a tube, but with a butted mandrel inside. If you want to cold draw other tubes, you use the same machine with the appropriate dies and without a butted mandrel. The butting process is just a modification of cold drawing. I don't know what Reynolds finds economical to do in house versus contracting out, but Reynolds is a tubing specialist, and it's not that unusual for tubing specialists to have this capability, even if they bring in seamless stock from outside. For non-cycling applications, butting is merely optional. I don't know what percent of sales is B2B non-cycling tubing and what percent is consumer facing cycling tubing, but non-cycling and non-butted tubes are part or Reynold's business. Reynolds says both that 631(853) is prone to work hardening, but is also suitable for the frame builder to manipulate cold. When I say that the tubes are annealed some point soon before leaving the factory, I mean that not much occurs after annealing, and that only minimal or no cold working has been done since the last annealing, not that they anneal them the last minute right before being loaded onto the truck.