My friend & I both have the Rem. 700 ML and both switched to the Triple 7 this year (for cleaning purposes). He started getting double bangs and thought his pellets may have picked up some moisture. He switched back to his Pyrodex and had no problems as it fired just fine. I didn't have any problems initially, but just yesterday started getting hang fires and double bangs. After some reluctance, I switched back to the Pyrodex pellets and my problems are gone.

Therefore, at least in both our situations we concluded that it must be the Triple 7 pellets.