F-I-C,Mike brings up a good point a diaphragm needs to stay stationary at the roof of your mouth to work properly,and the key is finding one that fits your pallet to where it does'nt slide all over the place.If air gets around the call it wont function right and if the call is sliding around at the roof of your mouth thats what happens.Sometimes it may take awhile to break-in a call to where it does'nt do this,or you can make it fit better by trimming the outside materail off.Some campanys like Quakerboy make large and small frame calls or like H.S.struts alumi line of diaphragms calls you can bend the frame to make it fit better.I've tried a few of Primos diaphragms before and they did not fit my pallet comfortably enough to satisfy me,but that does'nt mean it wont work for you.H.S.strut sells a video called &quot;So You want to be a Turkey Hunter&quot;that covers calls and calling that may help. They also have a series of videos called H.S strut University series dealing with specific calls such as mouth,friction,box,and locater calls,that include a call and the video and how to use it.Cabelas carrys it!Hope this helps. <img src=icon_smile_big.gif border=0 align=middle>