Most federal ammunition now a days has those new Flite Control Wads that open at the rear rather than the front. The idea is for the wad to stay with the shot charge longer than a conventional wad. A patternmaster, however, works exactly the opposite way. The studs on the inside of the choke are designed to literally strip the wadding from the shot colum just before it passes through the choke and out the barrel. Flite Control wads are much stiffer and thicker than convential wads, the results will leave you with a very very dirty and plastic gummed choke tube. Moreover, the extra money you pay for the flite control wad (and I have my own opinions about that anyway) will be totally for nothing because all you are doing is ripping it up anyway.