Remington 742 & 7400 locking lug collar remove from barrel.

[264killer]

Is collar sweated on or threaded on to barrel? I have a 30-06 742 barrel & a 270 caliber 7400 barrel . Want to switch them so I can use the 06 barrel on the 7400. I would buy a 06 or 308 barrel for the Remington 7400 if i could find one.