I just upgrade from a 38 airweight to a M&P 340, mainly for the better sights (old eyes). Was firing it today with .357 ammo and the bullets were coming out on the fourth and fifth round. Even had a fifth round come out so far as to bind the cylinder. What ammo is everyone using in these guns, that is reliable? I think S&W states that you have to use over 120 grain bullets in these guns and I was firing 158 grain loads, having this problem.