I have been making jams for 20 years, but until today I had never heard of not using pectin to make it jell. Well, I found a recipe on Epicurious that has made me a believer (at least for raspberry jam). It jelled just great and has the most intense raspberry flavor I have ever encountered outside of a pie. I varied the recipe only slightly, using 5 cups of raspberries and 3 cups of sugar. I used the water bath method of processing and processed for 12 minutes due to the altitude. Here is the link to the recipe.
Old Fashioned Raspberry Jam