According to mossberg its a 6+1 SKU
50700
Gauge
.410 Bore
Action Type
Pump-Action
Chamber Size
3"
Usage
Security
Barrel Length
18.5"
Barrel Finish
Matte Blue
Choke
Cylinder Bore
Capacity
6+1
Length
40"
LOP
13.87"
LOP Type
Fixed
Sights
Bead
Stock
Synthetic (Black)
Weight
7
UPC
015813507004

Hi Ben, I disagree with the other answers.
The magazine tube provides a 6+1 ammunition capacity when loaded with 2.5” shells, or a 5+1 capacity when using 3” shells.
The barrel is 18.5", so look at the mag tube compared to the barrel. There is no way it can hold (6) 3" shells.
Read it in this review (go down to 5th paragraph) >>> nrawomen.com/content/review-mossberg-590-7-shot-410-bore-shotgun
Stay safe & have a great day!

7 + 1 with 2.5 inch shells and 6 + 1 with 3-inch shells.

Hi Ben and welcome. It is a 7 + 1 with 2,5-inch shells and 6 + 1 with 3-inch shells. Cheers, stay safe and enjoy!

Good evening to you!! The Mossberg & Sons 590 PERSUADER 410/18.5 has a capacity of 7+1 rounds. Size of cartridges will dictate overall capacity. 7rds are figure using 3" shells. Hope this helps. Have a good night.