Striker easily. 100 shells; enough said.
I use the riot gun on castle actually. Yeah narrower damage spread is nice since the plaga parasites in castle can instantly kill you and that's kinda where riot gun shines, more so than the normal shotgun.You shouldn't ever need 100 shells even on pro otherwise you're doing something wrong imo.
I chose the Riot Gun due to it's functionality. It has the best maneuverability while aiming as well as a narrower damage spread that makes well placed shots more effective. The spread on the Striker is godawful.
Both have same close range firepower, but Riot Gun has better long range damage & shoulder aim for easier to headshot, while Striker had higher capacity & wider spread for great up close shooting.I think riot is the best, probably had more fire power
But when Striker is available i take it because of the unique feature regarding ammo capacity