I'm working some loads for my 7mm WSM built with a 26 1/2 barrel on a Montana Action. The bullet I've chosen is the Berger 140 gr. VLD and I've had some good success with IMR 4831. Right now my load gives me 3400 fps. with accuracy around .5 min at 200 yards but I'm plagued by the occasional flyer. All my brass have the necks turned and are weighed. Primers used are the Federal 215M. I'm looking to develop a load using Mag Pro or maybe H4831SC. My load with IMR 4831 is 66.5 gr. What I'm hoping to do is save a few bullets and powder in my search for a better load since both can be hard to come by at times. If anyone has experience with those two powders I would appreciate some input.