Quote Originally Posted by MarkCO View Post
Yes, they are going to get a bit more fouling than a piston. I found a little faster powder to make sure that the powder is all burned before it gets to the gas port helps a good deal. Use slow powder like Varget, it will be a mess.
I agree. Choosing the right powder probably makes the biggest difference in how clean the DI system runs. Personally, I've had good results with H335. Admittedly, I haven't tried everything out there. Is there one you prefer that runs really clean?