Yes, you CAN put any Remington 870 barrel on any Remington 870 shotgun (taking into consideration you're using the same gauge!), EXCEPT for the following:
870 SuperMag. The barrel is different. (If I'm not mistaken, the 'tab' on the chamber end of the barrel is longer. The barrel ring may be in a different location, too.)
870 Special Field. The barrel ring is farther back on the barrel.
Now, the barrel nut/cap retention method (old vs. new) is a totally different issue.
However, you CAN swap barrels.
G21 Gen2; G19 Gen3; G30SF; G23 Gen3; G26 Gen4. GLOCK Certified Armorer
"Live Free. Practice democracy. Make a difference. Love your family and your country." H.N.K. (My Dad) 09/02/1924 - 05/11/2012
Last edited by byf43; 02-27-2010 at 10:26..