I've been using Jon Cone's refillable cartridges on my 3800 for about 2 years and they've operated perfectly. But you have to keep two things in mind with these carts. To initiate first time ink flow or if you let them run to empty, you have to prime them by drawing any air and first ink flow with the syringe that comes with the cart. Also, you need to check the carts from time to time because the 3800 will always show them to be full regardless of how much ink remains.
Les