Correct you cant see the port. With zero leading that I can actual see building up any where I feel confident that there will be no lead build up in the gas port that would affect function. I'm only in my trial stage for AR with cast. As I see it ammunition is going to become a bigger problem for us civilians in the not to near future so I want to at least have some sort of supply. I have only tried a few powders the last 100 or so where with H4895 following Hodgdon guide lines for reduced loads I have only begun. Over the winter I plan on mixing up a little harder alloy and push these pellets a bit faster in attempt to get decent accuracy and function of the rifle. Right now they are fun plinking lower recoil and rifle needs to be cycled by hand....I use a single shot mag for now. Figure I can at least have a cheap supply of bullets. I dumped 40 rounds of 30-06 cast through my garand with good results with only one load being able to eject a round but not picking up the next.
OP asked about crimping.....I answered I don't crimp except for a certain bullet with a very sharp edged flat base. Even with the chamfer on the inside have a tendency to "grab" the case . These bullets shoot well so I'm going to use them. With the lee die set I use if I don't skightly flare the case these bullets don't go in straight kink case mouths or shaves of jacket material.......only this particular bullet gives me issues. I have several thousand of them. The price I paid its well worth a little added step to make them work.....its also a good way to use up my Xx fired cases
I like what you are doing.......and the fact that ammo is scarce and increasing in price by quite a bit is exactly why I am starting to stock up on reloading equipment. I am just glad I saved all my brass. I also thought about casting into a home made jacket then resizing it after. Just a thought.