The Beretta 390 series are well designed shotguns which handle nicely and are very reliable with most loads. The gas valve system is designed to allow the shooter to use loads which vary from light to heavy magnum. While this system works very well for the occasional user; the avid hunter or target shooter may want to tailor their shotgun to a specific load or range of loads. The gas valve springs designed by Cole Gunsmithing allow the shooter to utilize the full potential of this design while increasing reliability, reducing felt recoil and premature parts wear.