I too use a Sprinco COR-BON device, together with a Wolff 21lbs recoil spring in my SIG P229/357SIG, works very well; didn't have any FTFs, FTEs yet with my handloads or Federal- and S&B Ammo, around 2ks til now; I don't shoot UMC in this caliber; slides always locks open after the last round...