Are the 870 Express and 870 Special Purpose barrels interchangeable?

[Regolith]

This would be good to know. I was trying to decide between getting the 20" Imp. Cyl. bore barrel for $140 and the 20" RemChoke barrel for $190 or so, and then I noticed that the RemChoke barrel is for the 12 Special Purpose, while the 20" Imp. Cyl specifies its for the 12 Express. The description at the head of the page on the Cabela's website (link below) warns that some models are not interchangeable, but doesn't specify in regards to the Special Purpose.

http://www.cabelas.com/cabelas/en/t...&parentType=index&indexId=cat20805&hasJS=true

I have the 12 gauge Express, if it matters.

 

[farscott]

The Special Field barrels are NOT interchangeable with the Express and Wingmaster as the barrel retaining ring is in a different location.

The Special Purpose barrels are interchangeable with the Express and Wingmaster barrels. Some Special Purpose barrels are parkerized, not blued.