I've found that keeping a fresh recoil spring in a M1 or M2 reduces the chance of a malfunction. Available in factory stock weight, reduced power and extra power (+25%) ratings. I use the reduced power spring in my gun but I know other really good shooters who prefer the extra power spring. I've also owned one M2 that just didn't work reliably with anything other than the factory weight spring. Fits M1, M2, Super 90, Super Black Eagle, and Montefeltro. Price is $13.99.
Wolff Benelli Shotgun Recoil Spring