Preheat oven to 250℉.
Wash and rinse jars. Put on a sheet pan into the oven to sterilize while making the jam.
Put the rings and lids into a pot with enough water to cover. Bring to a boil. Put the pot into the oven with the jars.
In a 2-3 quart pot add the raspberries, strawberries, lemon juice, sugar, and Calabrian chilies.
Bring to a boil, reduce to a simmer. Let simmer for 20-30 minutes until thickened, stirring occasionally. Stirring your spoon through it the jam should take a bit of time to come together behind the spoon.
Remove from heat. Skim off any foam.
Transfer to your prepared jars. Wipe rims, add lid and ring to finger-tight while still hot.
Let cool. Jars should seal from the heat of the jam. If they don't refrigerate those jars and eat first.