Questions about Remington 870 7-round barrel change
I recently bought a Remington 870 Express synthetic 7-round 18.5" for home defense. I also wanted to shoot skeet and trap etc, so I bought a 28" vent rib barrel made by Remington from cabelas. When I talked to the guy from cabelas he said that it should fit all 870 models, but it seems to me that it should only fit the 5 round guns.
When I take off the old barrel and slide the new one on there's several inches between the thumb screw magazine cap and the barrel guide ring, whereas the original 18.5" barrel is held on only by that magazine cap meeting the guide ring flush without gaps.
Are there separate barrels for different sized magazines, or is this normal for a large gap to be there and the only thing holding the barrel on seems to me to be friction?