I've always used the Halloween pumpkins. I scoop out as much of the inner pumpkin as I can( I use an ice cream scoop) and then make a Jack-o-Lantern, or I cut the pumpkin into chunks and then microwave until tender. I wait to peel the chunks until after it cools a bit. Then I run it through my blender until smooth, measure 2 cups (the amount for 1 pie) into a zippy bag and freeze.
Sometimes it's more watery than others and I will drain a bit before freezing.
I've done this for so long my family doesn't like the grocery store canned stuff.
There's no reason that I know of that you couldn't pressure cooker can it if you wanted. Just follow the directions for your pressure cooker.