I started with the Primos Pack Bugle then transitioned into diaphragm calls. At the beginning I would just gag, probably lasted almost a year. I kept after it then all of a sudden no gagging and I can make decent sounds. I have tried diaphragms from Primos, Rocky Mountain, and Phelps. I prefer the Phelps white ones but also use Corey Jacobsen's orange one which is made by Rocky Mountain. Thinking about getting one from Dirk Durham (The Bugler) but haven't pulled the trigger yet. Pretty sure it is made by Phelps. I also use the tube from Phelps.
Use and practice with diaphrams. I just switched to phelps bugle. Most realistic and ease of use bugle out there for crisp sounds. Of course, u need a lot of practice to match diaphrams to situations and sounds Everyone prefers different